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sqlite3.h
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00001 /*
00002 ** 2001 September 15
00003 **
00004 ** The author disclaims copyright to this source code.  In place of
00005 ** a legal notice, here is a blessing:
00006 **
00007 **    May you do good and not evil.
00008 **    May you find forgiveness for yourself and forgive others.
00009 **    May you share freely, never taking more than you give.
00010 **
00011 *************************************************************************
00012 ** This header file defines the interface that the SQLite library
00013 ** presents to client programs.  If a C-function, structure, datatype,
00014 ** or constant definition does not appear in this file, then it is
00015 ** not a published API of SQLite, is subject to change without
00016 ** notice, and should not be referenced by programs that use SQLite.
00017 **
00018 ** Some of the definitions that are in this file are marked as
00019 ** "experimental".  Experimental interfaces are normally new
00020 ** features recently added to SQLite.  We do not anticipate changes
00021 ** to experimental interfaces but reserve the right to make minor changes
00022 ** if experience from use "in the wild" suggest such changes are prudent.
00023 **
00024 ** The official C-language API documentation for SQLite is derived
00025 ** from comments in this file.  This file is the authoritative source
00026 ** on how SQLite interfaces are suppose to operate.
00027 **
00028 ** The name of this file under configuration management is "sqlite.h.in".
00029 ** The makefile makes some minor changes to this file (such as inserting
00030 ** the version number) and changes its name to "sqlite3.h" as
00031 ** part of the build process.
00032 */
00033 #ifndef _SQLITE3_H_
00034 #define _SQLITE3_H_
00035 #include <stdarg.h>     /* Needed for the definition of va_list */
00036 
00037 /*
00038 ** Make sure we can call this stuff from C++.
00039 */
00040 #ifdef __cplusplus
00041 extern "C" {
00042 #endif
00043 
00044 
00045 /*
00046 ** Add the ability to override 'extern'
00047 */
00048 #ifndef SQLITE_EXTERN
00049 # define SQLITE_EXTERN extern
00050 #endif
00051 
00052 #ifndef SQLITE_API
00053 # define SQLITE_API
00054 #endif
00055 
00056 
00057 /*
00058 ** These no-op macros are used in front of interfaces to mark those
00059 ** interfaces as either deprecated or experimental.  New applications
00060 ** should not use deprecated interfaces - they are support for backwards
00061 ** compatibility only.  Application writers should be aware that
00062 ** experimental interfaces are subject to change in point releases.
00063 **
00064 ** These macros used to resolve to various kinds of compiler magic that
00065 ** would generate warning messages when they were used.  But that
00066 ** compiler magic ended up generating such a flurry of bug reports
00067 ** that we have taken it all out and gone back to using simple
00068 ** noop macros.
00069 */
00070 #define SQLITE_DEPRECATED
00071 #define SQLITE_EXPERIMENTAL
00072 
00073 /*
00074 ** Ensure these symbols were not defined by some previous header file.
00075 */
00076 #ifdef SQLITE_VERSION
00077 # undef SQLITE_VERSION
00078 #endif
00079 #ifdef SQLITE_VERSION_NUMBER
00080 # undef SQLITE_VERSION_NUMBER
00081 #endif
00082 
00083 /*
00084 ** CAPI3REF: Compile-Time Library Version Numbers
00085 **
00086 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
00087 ** evaluates to a string literal that is the SQLite version in the
00088 ** format "X.Y.Z" where X is the major version number (always 3 for
00089 ** SQLite3) and Y is the minor version number and Z is the release number.)^
00090 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
00091 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
00092 ** numbers used in [SQLITE_VERSION].)^
00093 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
00094 ** be larger than the release from which it is derived.  Either Y will
00095 ** be held constant and Z will be incremented or else Y will be incremented
00096 ** and Z will be reset to zero.
00097 **
00098 ** Since version 3.6.18, SQLite source code has been stored in the
00099 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
00100 ** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
00101 ** a string which identifies a particular check-in of SQLite
00102 ** within its configuration management system.  ^The SQLITE_SOURCE_ID
00103 ** string contains the date and time of the check-in (UTC) and an SHA1
00104 ** hash of the entire source tree.
00105 **
00106 ** See also: [sqlite3_libversion()],
00107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
00108 ** [sqlite_version()] and [sqlite_source_id()].
00109 */
00110 #define SQLITE_VERSION        "3.7.7.1"
00111 #define SQLITE_VERSION_NUMBER 3007007
00112 #define SQLITE_SOURCE_ID      "2011-06-28 17:39:05 af0d91adf497f5f36ec3813f04235a6e195a605f"
00113 
00114 /*
00115 ** CAPI3REF: Run-Time Library Version Numbers
00116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
00117 **
00118 ** These interfaces provide the same information as the [SQLITE_VERSION],
00119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
00120 ** but are associated with the library instead of the header file.  ^(Cautious
00121 ** programmers might include assert() statements in their application to
00122 ** verify that values returned by these interfaces match the macros in
00123 ** the header, and thus insure that the application is
00124 ** compiled with matching library and header files.
00125 **
00126 ** <blockquote><pre>
00127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
00128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
00129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
00130 ** </pre></blockquote>)^
00131 **
00132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
00133 ** macro.  ^The sqlite3_libversion() function returns a pointer to the
00134 ** to the sqlite3_version[] string constant.  The sqlite3_libversion()
00135 ** function is provided for use in DLLs since DLL users usually do not have
00136 ** direct access to string constants within the DLL.  ^The
00137 ** sqlite3_libversion_number() function returns an integer equal to
00138 ** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns 
00139 ** a pointer to a string constant whose value is the same as the 
00140 ** [SQLITE_SOURCE_ID] C preprocessor macro.
00141 **
00142 ** See also: [sqlite_version()] and [sqlite_source_id()].
00143 */
00144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
00145 SQLITE_API const char *sqlite3_libversion(void);
00146 SQLITE_API const char *sqlite3_sourceid(void);
00147 SQLITE_API int sqlite3_libversion_number(void);
00148 
00149 /*
00150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
00151 **
00152 ** ^The sqlite3_compileoption_used() function returns 0 or 1 
00153 ** indicating whether the specified option was defined at 
00154 ** compile time.  ^The SQLITE_ prefix may be omitted from the 
00155 ** option name passed to sqlite3_compileoption_used().  
00156 **
00157 ** ^The sqlite3_compileoption_get() function allows iterating
00158 ** over the list of options that were defined at compile time by
00159 ** returning the N-th compile time option string.  ^If N is out of range,
00160 ** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_ 
00161 ** prefix is omitted from any strings returned by 
00162 ** sqlite3_compileoption_get().
00163 **
00164 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
00165 ** and sqlite3_compileoption_get() may be omitted by specifying the 
00166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
00167 **
00168 ** See also: SQL functions [sqlite_compileoption_used()] and
00169 ** [sqlite_compileoption_get()] and the [compile_options pragma].
00170 */
00171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
00172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
00173 SQLITE_API const char *sqlite3_compileoption_get(int N);
00174 #endif
00175 
00176 /*
00177 ** CAPI3REF: Test To See If The Library Is Threadsafe
00178 **
00179 ** ^The sqlite3_threadsafe() function returns zero if and only if
00180 ** SQLite was compiled mutexing code omitted due to the
00181 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
00182 **
00183 ** SQLite can be compiled with or without mutexes.  When
00184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
00185 ** are enabled and SQLite is threadsafe.  When the
00186 ** [SQLITE_THREADSAFE] macro is 0, 
00187 ** the mutexes are omitted.  Without the mutexes, it is not safe
00188 ** to use SQLite concurrently from more than one thread.
00189 **
00190 ** Enabling mutexes incurs a measurable performance penalty.
00191 ** So if speed is of utmost importance, it makes sense to disable
00192 ** the mutexes.  But for maximum safety, mutexes should be enabled.
00193 ** ^The default behavior is for mutexes to be enabled.
00194 **
00195 ** This interface can be used by an application to make sure that the
00196 ** version of SQLite that it is linking against was compiled with
00197 ** the desired setting of the [SQLITE_THREADSAFE] macro.
00198 **
00199 ** This interface only reports on the compile-time mutex setting
00200 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
00201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
00202 ** can be fully or partially disabled using a call to [sqlite3_config()]
00203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
00204 ** or [SQLITE_CONFIG_MUTEX].  ^(The return value of the
00205 ** sqlite3_threadsafe() function shows only the compile-time setting of
00206 ** thread safety, not any run-time changes to that setting made by
00207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
00208 ** is unchanged by calls to sqlite3_config().)^
00209 **
00210 ** See the [threading mode] documentation for additional information.
00211 */
00212 SQLITE_API int sqlite3_threadsafe(void);
00213 
00214 /*
00215 ** CAPI3REF: Database Connection Handle
00216 ** KEYWORDS: {database connection} {database connections}
00217 **
00218 ** Each open SQLite database is represented by a pointer to an instance of
00219 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
00220 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
00221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
00222 ** is its destructor.  There are many other interfaces (such as
00223 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
00224 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
00225 ** sqlite3 object.
00226 */
00227 typedef struct sqlite3 sqlite3;
00228 
00229 /*
00230 ** CAPI3REF: 64-Bit Integer Types
00231 ** KEYWORDS: sqlite_int64 sqlite_uint64
00232 **
00233 ** Because there is no cross-platform way to specify 64-bit integer types
00234 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
00235 **
00236 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
00237 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
00238 ** compatibility only.
00239 **
00240 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
00241 ** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
00242 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 
00243 ** between 0 and +18446744073709551615 inclusive.
00244 */
00245 #ifdef SQLITE_INT64_TYPE
00246   typedef SQLITE_INT64_TYPE sqlite_int64;
00247   typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
00248 #elif defined(_MSC_VER) || defined(__BORLANDC__)
00249   typedef __int64 sqlite_int64;
00250   typedef unsigned __int64 sqlite_uint64;
00251 #else
00252   typedef long long int sqlite_int64;
00253   typedef unsigned long long int sqlite_uint64;
00254 #endif
00255 typedef sqlite_int64 sqlite3_int64;
00256 typedef sqlite_uint64 sqlite3_uint64;
00257 
00258 /*
00259 ** If compiling for a processor that lacks floating point support,
00260 ** substitute integer for floating-point.
00261 */
00262 #ifdef SQLITE_OMIT_FLOATING_POINT
00263 # define double sqlite3_int64
00264 #endif
00265 
00266 /*
00267 ** CAPI3REF: Closing A Database Connection
00268 **
00269 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object.
00270 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is
00271 ** successfully destroyed and all associated resources are deallocated.
00272 **
00273 ** Applications must [sqlite3_finalize | finalize] all [prepared statements]
00274 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
00275 ** the [sqlite3] object prior to attempting to close the object.  ^If
00276 ** sqlite3_close() is called on a [database connection] that still has
00277 ** outstanding [prepared statements] or [BLOB handles], then it returns
00278 ** SQLITE_BUSY.
00279 **
00280 ** ^If [sqlite3_close()] is invoked while a transaction is open,
00281 ** the transaction is automatically rolled back.
00282 **
00283 ** The C parameter to [sqlite3_close(C)] must be either a NULL
00284 ** pointer or an [sqlite3] object pointer obtained
00285 ** from [sqlite3_open()], [sqlite3_open16()], or
00286 ** [sqlite3_open_v2()], and not previously closed.
00287 ** ^Calling sqlite3_close() with a NULL pointer argument is a 
00288 ** harmless no-op.
00289 */
00290 SQLITE_API int sqlite3_close(sqlite3 *);
00291 
00292 /*
00293 ** The type for a callback function.
00294 ** This is legacy and deprecated.  It is included for historical
00295 ** compatibility and is not documented.
00296 */
00297 typedef int (*sqlite3_callback)(void*,int,char**, char**);
00298 
00299 /*
00300 ** CAPI3REF: One-Step Query Execution Interface
00301 **
00302 ** The sqlite3_exec() interface is a convenience wrapper around
00303 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
00304 ** that allows an application to run multiple statements of SQL
00305 ** without having to use a lot of C code. 
00306 **
00307 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
00308 ** semicolon-separate SQL statements passed into its 2nd argument,
00309 ** in the context of the [database connection] passed in as its 1st
00310 ** argument.  ^If the callback function of the 3rd argument to
00311 ** sqlite3_exec() is not NULL, then it is invoked for each result row
00312 ** coming out of the evaluated SQL statements.  ^The 4th argument to
00313 ** sqlite3_exec() is relayed through to the 1st argument of each
00314 ** callback invocation.  ^If the callback pointer to sqlite3_exec()
00315 ** is NULL, then no callback is ever invoked and result rows are
00316 ** ignored.
00317 **
00318 ** ^If an error occurs while evaluating the SQL statements passed into
00319 ** sqlite3_exec(), then execution of the current statement stops and
00320 ** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
00321 ** is not NULL then any error message is written into memory obtained
00322 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
00323 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
00324 ** on error message strings returned through the 5th parameter of
00325 ** of sqlite3_exec() after the error message string is no longer needed.
00326 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
00327 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
00328 ** NULL before returning.
00329 **
00330 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
00331 ** routine returns SQLITE_ABORT without invoking the callback again and
00332 ** without running any subsequent SQL statements.
00333 **
00334 ** ^The 2nd argument to the sqlite3_exec() callback function is the
00335 ** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
00336 ** callback is an array of pointers to strings obtained as if from
00337 ** [sqlite3_column_text()], one for each column.  ^If an element of a
00338 ** result row is NULL then the corresponding string pointer for the
00339 ** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
00340 ** sqlite3_exec() callback is an array of pointers to strings where each
00341 ** entry represents the name of corresponding result column as obtained
00342 ** from [sqlite3_column_name()].
00343 **
00344 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
00345 ** to an empty string, or a pointer that contains only whitespace and/or 
00346 ** SQL comments, then no SQL statements are evaluated and the database
00347 ** is not changed.
00348 **
00349 ** Restrictions:
00350 **
00351 ** <ul>
00352 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
00353 **      is a valid and open [database connection].
00354 ** <li> The application must not close [database connection] specified by
00355 **      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
00356 ** <li> The application must not modify the SQL statement text passed into
00357 **      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
00358 ** </ul>
00359 */
00360 SQLITE_API int sqlite3_exec(
00361   sqlite3*,                                  /* An open database */
00362   const char *sql,                           /* SQL to be evaluated */
00363   int (*callback)(void*,int,char**,char**),  /* Callback function */
00364   void *,                                    /* 1st argument to callback */
00365   char **errmsg                              /* Error msg written here */
00366 );
00367 
00368 /*
00369 ** CAPI3REF: Result Codes
00370 ** KEYWORDS: SQLITE_OK {error code} {error codes}
00371 ** KEYWORDS: {result code} {result codes}
00372 **
00373 ** Many SQLite functions return an integer result code from the set shown
00374 ** here in order to indicates success or failure.
00375 **
00376 ** New error codes may be added in future versions of SQLite.
00377 **
00378 ** See also: [SQLITE_IOERR_READ | extended result codes],
00379 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
00380 */
00381 #define SQLITE_OK           0   /* Successful result */
00382 /* beginning-of-error-codes */
00383 #define SQLITE_ERROR        1   /* SQL error or missing database */
00384 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
00385 #define SQLITE_PERM         3   /* Access permission denied */
00386 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
00387 #define SQLITE_BUSY         5   /* The database file is locked */
00388 #define SQLITE_LOCKED       6   /* A table in the database is locked */
00389 #define SQLITE_NOMEM        7   /* A malloc() failed */
00390 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
00391 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
00392 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
00393 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
00394 #define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
00395 #define SQLITE_FULL        13   /* Insertion failed because database is full */
00396 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
00397 #define SQLITE_PROTOCOL    15   /* Database lock protocol error */
00398 #define SQLITE_EMPTY       16   /* Database is empty */
00399 #define SQLITE_SCHEMA      17   /* The database schema changed */
00400 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
00401 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
00402 #define SQLITE_MISMATCH    20   /* Data type mismatch */
00403 #define SQLITE_MISUSE      21   /* Library used incorrectly */
00404 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
00405 #define SQLITE_AUTH        23   /* Authorization denied */
00406 #define SQLITE_FORMAT      24   /* Auxiliary database format error */
00407 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
00408 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
00409 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
00410 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
00411 /* end-of-error-codes */
00412 
00413 /*
00414 ** CAPI3REF: Extended Result Codes
00415 ** KEYWORDS: {extended error code} {extended error codes}
00416 ** KEYWORDS: {extended result code} {extended result codes}
00417 **
00418 ** In its default configuration, SQLite API routines return one of 26 integer
00419 ** [SQLITE_OK | result codes].  However, experience has shown that many of
00420 ** these result codes are too coarse-grained.  They do not provide as
00421 ** much information about problems as programmers might like.  In an effort to
00422 ** address this, newer versions of SQLite (version 3.3.8 and later) include
00423 ** support for additional result codes that provide more detailed information
00424 ** about errors. The extended result codes are enabled or disabled
00425 ** on a per database connection basis using the
00426 ** [sqlite3_extended_result_codes()] API.
00427 **
00428 ** Some of the available extended result codes are listed here.
00429 ** One may expect the number of extended result codes will be expand
00430 ** over time.  Software that uses extended result codes should expect
00431 ** to see new result codes in future releases of SQLite.
00432 **
00433 ** The SQLITE_OK result code will never be extended.  It will always
00434 ** be exactly zero.
00435 */
00436 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
00437 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
00438 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
00439 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
00440 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
00441 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
00442 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
00443 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
00444 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
00445 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
00446 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
00447 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
00448 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
00449 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
00450 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
00451 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
00452 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
00453 #define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
00454 #define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
00455 #define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
00456 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
00457 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
00458 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
00459 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
00460 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
00461 #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
00462 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
00463 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
00464 
00465 /*
00466 ** CAPI3REF: Flags For File Open Operations
00467 **
00468 ** These bit values are intended for use in the
00469 ** 3rd parameter to the [sqlite3_open_v2()] interface and
00470 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
00471 */
00472 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
00473 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
00474 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
00475 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
00476 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
00477 #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
00478 #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
00479 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
00480 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
00481 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
00482 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
00483 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
00484 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
00485 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
00486 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
00487 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
00488 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
00489 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
00490 #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
00491 
00492 /* Reserved:                         0x00F00000 */
00493 
00494 /*
00495 ** CAPI3REF: Device Characteristics
00496 **
00497 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
00498 ** object returns an integer which is a vector of the these
00499 ** bit values expressing I/O characteristics of the mass storage
00500 ** device that holds the file that the [sqlite3_io_methods]
00501 ** refers to.
00502 **
00503 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
00504 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
00505 ** mean that writes of blocks that are nnn bytes in size and
00506 ** are aligned to an address which is an integer multiple of
00507 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
00508 ** that when data is appended to a file, the data is appended
00509 ** first then the size of the file is extended, never the other
00510 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
00511 ** information is written to disk in the same order as calls
00512 ** to xWrite().
00513 */
00514 #define SQLITE_IOCAP_ATOMIC                 0x00000001
00515 #define SQLITE_IOCAP_ATOMIC512              0x00000002
00516 #define SQLITE_IOCAP_ATOMIC1K               0x00000004
00517 #define SQLITE_IOCAP_ATOMIC2K               0x00000008
00518 #define SQLITE_IOCAP_ATOMIC4K               0x00000010
00519 #define SQLITE_IOCAP_ATOMIC8K               0x00000020
00520 #define SQLITE_IOCAP_ATOMIC16K              0x00000040
00521 #define SQLITE_IOCAP_ATOMIC32K              0x00000080
00522 #define SQLITE_IOCAP_ATOMIC64K              0x00000100
00523 #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
00524 #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
00525 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
00526 
00527 /*
00528 ** CAPI3REF: File Locking Levels
00529 **
00530 ** SQLite uses one of these integer values as the second
00531 ** argument to calls it makes to the xLock() and xUnlock() methods
00532 ** of an [sqlite3_io_methods] object.
00533 */
00534 #define SQLITE_LOCK_NONE          0
00535 #define SQLITE_LOCK_SHARED        1
00536 #define SQLITE_LOCK_RESERVED      2
00537 #define SQLITE_LOCK_PENDING       3
00538 #define SQLITE_LOCK_EXCLUSIVE     4
00539 
00540 /*
00541 ** CAPI3REF: Synchronization Type Flags
00542 **
00543 ** When SQLite invokes the xSync() method of an
00544 ** [sqlite3_io_methods] object it uses a combination of
00545 ** these integer values as the second argument.
00546 **
00547 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
00548 ** sync operation only needs to flush data to mass storage.  Inode
00549 ** information need not be flushed. If the lower four bits of the flag
00550 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
00551 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
00552 ** to use Mac OS X style fullsync instead of fsync().
00553 **
00554 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
00555 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
00556 ** settings.  The [synchronous pragma] determines when calls to the
00557 ** xSync VFS method occur and applies uniformly across all platforms.
00558 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
00559 ** energetic or rigorous or forceful the sync operations are and
00560 ** only make a difference on Mac OSX for the default SQLite code.
00561 ** (Third-party VFS implementations might also make the distinction
00562 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
00563 ** operating systems natively supported by SQLite, only Mac OSX
00564 ** cares about the difference.)
00565 */
00566 #define SQLITE_SYNC_NORMAL        0x00002
00567 #define SQLITE_SYNC_FULL          0x00003
00568 #define SQLITE_SYNC_DATAONLY      0x00010
00569 
00570 /*
00571 ** CAPI3REF: OS Interface Open File Handle
00572 **
00573 ** An [sqlite3_file] object represents an open file in the 
00574 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
00575 ** implementations will
00576 ** want to subclass this object by appending additional fields
00577 ** for their own use.  The pMethods entry is a pointer to an
00578 ** [sqlite3_io_methods] object that defines methods for performing
00579 ** I/O operations on the open file.
00580 */
00581 typedef struct sqlite3_file sqlite3_file;
00582 struct sqlite3_file {
00583   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
00584 };
00585 
00586 /*
00587 ** CAPI3REF: OS Interface File Virtual Methods Object
00588 **
00589 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
00590 ** [sqlite3_file] object (or, more commonly, a subclass of the
00591 ** [sqlite3_file] object) with a pointer to an instance of this object.
00592 ** This object defines the methods used to perform various operations
00593 ** against the open file represented by the [sqlite3_file] object.
00594 **
00595 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 
00596 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
00597 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
00598 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
00599 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
00600 ** to NULL.
00601 **
00602 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
00603 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
00604 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
00605 ** flag may be ORed in to indicate that only the data of the file
00606 ** and not its inode needs to be synced.
00607 **
00608 ** The integer values to xLock() and xUnlock() are one of
00609 ** <ul>
00610 ** <li> [SQLITE_LOCK_NONE],
00611 ** <li> [SQLITE_LOCK_SHARED],
00612 ** <li> [SQLITE_LOCK_RESERVED],
00613 ** <li> [SQLITE_LOCK_PENDING], or
00614 ** <li> [SQLITE_LOCK_EXCLUSIVE].
00615 ** </ul>
00616 ** xLock() increases the lock. xUnlock() decreases the lock.
00617 ** The xCheckReservedLock() method checks whether any database connection,
00618 ** either in this process or in some other process, is holding a RESERVED,
00619 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
00620 ** if such a lock exists and false otherwise.
00621 **
00622 ** The xFileControl() method is a generic interface that allows custom
00623 ** VFS implementations to directly control an open file using the
00624 ** [sqlite3_file_control()] interface.  The second "op" argument is an
00625 ** integer opcode.  The third argument is a generic pointer intended to
00626 ** point to a structure that may contain arguments or space in which to
00627 ** write return values.  Potential uses for xFileControl() might be
00628 ** functions to enable blocking locks with timeouts, to change the
00629 ** locking strategy (for example to use dot-file locks), to inquire
00630 ** about the status of a lock, or to break stale locks.  The SQLite
00631 ** core reserves all opcodes less than 100 for its own use.
00632 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
00633 ** Applications that define a custom xFileControl method should use opcodes
00634 ** greater than 100 to avoid conflicts.  VFS implementations should
00635 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
00636 ** recognize.
00637 **
00638 ** The xSectorSize() method returns the sector size of the
00639 ** device that underlies the file.  The sector size is the
00640 ** minimum write that can be performed without disturbing
00641 ** other bytes in the file.  The xDeviceCharacteristics()
00642 ** method returns a bit vector describing behaviors of the
00643 ** underlying device:
00644 **
00645 ** <ul>
00646 ** <li> [SQLITE_IOCAP_ATOMIC]
00647 ** <li> [SQLITE_IOCAP_ATOMIC512]
00648 ** <li> [SQLITE_IOCAP_ATOMIC1K]
00649 ** <li> [SQLITE_IOCAP_ATOMIC2K]
00650 ** <li> [SQLITE_IOCAP_ATOMIC4K]
00651 ** <li> [SQLITE_IOCAP_ATOMIC8K]
00652 ** <li> [SQLITE_IOCAP_ATOMIC16K]
00653 ** <li> [SQLITE_IOCAP_ATOMIC32K]
00654 ** <li> [SQLITE_IOCAP_ATOMIC64K]
00655 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
00656 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
00657 ** </ul>
00658 **
00659 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
00660 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
00661 ** mean that writes of blocks that are nnn bytes in size and
00662 ** are aligned to an address which is an integer multiple of
00663 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
00664 ** that when data is appended to a file, the data is appended
00665 ** first then the size of the file is extended, never the other
00666 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
00667 ** information is written to disk in the same order as calls
00668 ** to xWrite().
00669 **
00670 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
00671 ** in the unread portions of the buffer with zeros.  A VFS that
00672 ** fails to zero-fill short reads might seem to work.  However,
00673 ** failure to zero-fill short reads will eventually lead to
00674 ** database corruption.
00675 */
00676 typedef struct sqlite3_io_methods sqlite3_io_methods;
00677 struct sqlite3_io_methods {
00678   int iVersion;
00679   int (*xClose)(sqlite3_file*);
00680   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
00681   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
00682   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
00683   int (*xSync)(sqlite3_file*, int flags);
00684   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
00685   int (*xLock)(sqlite3_file*, int);
00686   int (*xUnlock)(sqlite3_file*, int);
00687   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
00688   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
00689   int (*xSectorSize)(sqlite3_file*);
00690   int (*xDeviceCharacteristics)(sqlite3_file*);
00691   /* Methods above are valid for version 1 */
00692   int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
00693   int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
00694   void (*xShmBarrier)(sqlite3_file*);
00695   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
00696   /* Methods above are valid for version 2 */
00697   /* Additional methods may be added in future releases */
00698 };
00699 
00700 /*
00701 ** CAPI3REF: Standard File Control Opcodes
00702 **
00703 ** These integer constants are opcodes for the xFileControl method
00704 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
00705 ** interface.
00706 **
00707 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
00708 ** opcode causes the xFileControl method to write the current state of
00709 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
00710 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
00711 ** into an integer that the pArg argument points to. This capability
00712 ** is used during testing and only needs to be supported when SQLITE_TEST
00713 ** is defined.
00714 **
00715 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
00716 ** layer a hint of how large the database file will grow to be during the
00717 ** current transaction.  This hint is not guaranteed to be accurate but it
00718 ** is often close.  The underlying VFS might choose to preallocate database
00719 ** file space based on this hint in order to help writes to the database
00720 ** file run faster.
00721 **
00722 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
00723 ** extends and truncates the database file in chunks of a size specified
00724 ** by the user. The fourth argument to [sqlite3_file_control()] should 
00725 ** point to an integer (type int) containing the new chunk-size to use
00726 ** for the nominated database. Allocating database file space in large
00727 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
00728 ** improve performance on some systems.
00729 **
00730 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
00731 ** to the [sqlite3_file] object associated with a particular database
00732 ** connection.  See the [sqlite3_file_control()] documentation for
00733 ** additional information.
00734 **
00735 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
00736 ** SQLite and sent to all VFSes in place of a call to the xSync method
00737 ** when the database connection has [PRAGMA synchronous] set to OFF.)^
00738 ** Some specialized VFSes need this signal in order to operate correctly
00739 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 
00740 ** VFSes do not need this signal and should silently ignore this opcode.
00741 ** Applications should not call [sqlite3_file_control()] with this
00742 ** opcode as doing so may disrupt the operation of the specialized VFSes
00743 ** that do require it.  
00744 */
00745 #define SQLITE_FCNTL_LOCKSTATE        1
00746 #define SQLITE_GET_LOCKPROXYFILE      2
00747 #define SQLITE_SET_LOCKPROXYFILE      3
00748 #define SQLITE_LAST_ERRNO             4
00749 #define SQLITE_FCNTL_SIZE_HINT        5
00750 #define SQLITE_FCNTL_CHUNK_SIZE       6
00751 #define SQLITE_FCNTL_FILE_POINTER     7
00752 #define SQLITE_FCNTL_SYNC_OMITTED     8
00753 
00754 
00755 /*
00756 ** CAPI3REF: Mutex Handle
00757 **
00758 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
00759 ** abstract type for a mutex object.  The SQLite core never looks
00760 ** at the internal representation of an [sqlite3_mutex].  It only
00761 ** deals with pointers to the [sqlite3_mutex] object.
00762 **
00763 ** Mutexes are created using [sqlite3_mutex_alloc()].
00764 */
00765 typedef struct sqlite3_mutex sqlite3_mutex;
00766 
00767 /*
00768 ** CAPI3REF: OS Interface Object
00769 **
00770 ** An instance of the sqlite3_vfs object defines the interface between
00771 ** the SQLite core and the underlying operating system.  The "vfs"
00772 ** in the name of the object stands for "virtual file system".  See
00773 ** the [VFS | VFS documentation] for further information.
00774 **
00775 ** The value of the iVersion field is initially 1 but may be larger in
00776 ** future versions of SQLite.  Additional fields may be appended to this
00777 ** object when the iVersion value is increased.  Note that the structure
00778 ** of the sqlite3_vfs object changes in the transaction between
00779 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
00780 ** modified.
00781 **
00782 ** The szOsFile field is the size of the subclassed [sqlite3_file]
00783 ** structure used by this VFS.  mxPathname is the maximum length of
00784 ** a pathname in this VFS.
00785 **
00786 ** Registered sqlite3_vfs objects are kept on a linked list formed by
00787 ** the pNext pointer.  The [sqlite3_vfs_register()]
00788 ** and [sqlite3_vfs_unregister()] interfaces manage this list
00789 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
00790 ** searches the list.  Neither the application code nor the VFS
00791 ** implementation should use the pNext pointer.
00792 **
00793 ** The pNext field is the only field in the sqlite3_vfs
00794 ** structure that SQLite will ever modify.  SQLite will only access
00795 ** or modify this field while holding a particular static mutex.
00796 ** The application should never modify anything within the sqlite3_vfs
00797 ** object once the object has been registered.
00798 **
00799 ** The zName field holds the name of the VFS module.  The name must
00800 ** be unique across all VFS modules.
00801 **
00802 ** [[sqlite3_vfs.xOpen]]
00803 ** ^SQLite guarantees that the zFilename parameter to xOpen
00804 ** is either a NULL pointer or string obtained
00805 ** from xFullPathname() with an optional suffix added.
00806 ** ^If a suffix is added to the zFilename parameter, it will
00807 ** consist of a single "-" character followed by no more than
00808 ** 10 alphanumeric and/or "-" characters.
00809 ** ^SQLite further guarantees that
00810 ** the string will be valid and unchanged until xClose() is
00811 ** called. Because of the previous sentence,
00812 ** the [sqlite3_file] can safely store a pointer to the
00813 ** filename if it needs to remember the filename for some reason.
00814 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
00815 ** must invent its own temporary name for the file.  ^Whenever the 
00816 ** xFilename parameter is NULL it will also be the case that the
00817 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
00818 **
00819 ** The flags argument to xOpen() includes all bits set in
00820 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
00821 ** or [sqlite3_open16()] is used, then flags includes at least
00822 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 
00823 ** If xOpen() opens a file read-only then it sets *pOutFlags to
00824 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
00825 **
00826 ** ^(SQLite will also add one of the following flags to the xOpen()
00827 ** call, depending on the object being opened:
00828 **
00829 ** <ul>
00830 ** <li>  [SQLITE_OPEN_MAIN_DB]
00831 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
00832 ** <li>  [SQLITE_OPEN_TEMP_DB]
00833 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
00834 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
00835 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
00836 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
00837 ** <li>  [SQLITE_OPEN_WAL]
00838 ** </ul>)^
00839 **
00840 ** The file I/O implementation can use the object type flags to
00841 ** change the way it deals with files.  For example, an application
00842 ** that does not care about crash recovery or rollback might make
00843 ** the open of a journal file a no-op.  Writes to this journal would
00844 ** also be no-ops, and any attempt to read the journal would return
00845 ** SQLITE_IOERR.  Or the implementation might recognize that a database
00846 ** file will be doing page-aligned sector reads and writes in a random
00847 ** order and set up its I/O subsystem accordingly.
00848 **
00849 ** SQLite might also add one of the following flags to the xOpen method:
00850 **
00851 ** <ul>
00852 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
00853 ** <li> [SQLITE_OPEN_EXCLUSIVE]
00854 ** </ul>
00855 **
00856 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
00857 ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
00858 ** will be set for TEMP databases and their journals, transient
00859 ** databases, and subjournals.
00860 **
00861 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
00862 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
00863 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
00864 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 
00865 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
00866 ** be created, and that it is an error if it already exists.
00867 ** It is <i>not</i> used to indicate the file should be opened 
00868 ** for exclusive access.
00869 **
00870 ** ^At least szOsFile bytes of memory are allocated by SQLite
00871 ** to hold the  [sqlite3_file] structure passed as the third
00872 ** argument to xOpen.  The xOpen method does not have to
00873 ** allocate the structure; it should just fill it in.  Note that
00874 ** the xOpen method must set the sqlite3_file.pMethods to either
00875 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
00876 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
00877 ** element will be valid after xOpen returns regardless of the success
00878 ** or failure of the xOpen call.
00879 **
00880 ** [[sqlite3_vfs.xAccess]]
00881 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
00882 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
00883 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
00884 ** to test whether a file is at least readable.   The file can be a
00885 ** directory.
00886 **
00887 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
00888 ** output buffer xFullPathname.  The exact size of the output buffer
00889 ** is also passed as a parameter to both  methods. If the output buffer
00890 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
00891 ** handled as a fatal error by SQLite, vfs implementations should endeavor
00892 ** to prevent this by setting mxPathname to a sufficiently large value.
00893 **
00894 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
00895 ** interfaces are not strictly a part of the filesystem, but they are
00896 ** included in the VFS structure for completeness.
00897 ** The xRandomness() function attempts to return nBytes bytes
00898 ** of good-quality randomness into zOut.  The return value is
00899 ** the actual number of bytes of randomness obtained.
00900 ** The xSleep() method causes the calling thread to sleep for at
00901 ** least the number of microseconds given.  ^The xCurrentTime()
00902 ** method returns a Julian Day Number for the current date and time as
00903 ** a floating point value.
00904 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
00905 ** Day Number multiplied by 86400000 (the number of milliseconds in 
00906 ** a 24-hour day).  
00907 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
00908 ** date and time if that method is available (if iVersion is 2 or 
00909 ** greater and the function pointer is not NULL) and will fall back
00910 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
00911 **
00912 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
00913 ** are not used by the SQLite core.  These optional interfaces are provided
00914 ** by some VFSes to facilitate testing of the VFS code. By overriding 
00915 ** system calls with functions under its control, a test program can
00916 ** simulate faults and error conditions that would otherwise be difficult
00917 ** or impossible to induce.  The set of system calls that can be overridden
00918 ** varies from one VFS to another, and from one version of the same VFS to the
00919 ** next.  Applications that use these interfaces must be prepared for any
00920 ** or all of these interfaces to be NULL or for their behavior to change
00921 ** from one release to the next.  Applications must not attempt to access
00922 ** any of these methods if the iVersion of the VFS is less than 3.
00923 */
00924 typedef struct sqlite3_vfs sqlite3_vfs;
00925 typedef void (*sqlite3_syscall_ptr)(void);
00926 struct sqlite3_vfs {
00927   int iVersion;            /* Structure version number (currently 3) */
00928   int szOsFile;            /* Size of subclassed sqlite3_file */
00929   int mxPathname;          /* Maximum file pathname length */
00930   sqlite3_vfs *pNext;      /* Next registered VFS */
00931   const char *zName;       /* Name of this virtual file system */
00932   void *pAppData;          /* Pointer to application-specific data */
00933   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
00934                int flags, int *pOutFlags);
00935   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
00936   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
00937   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
00938   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
00939   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
00940   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
00941   void (*xDlClose)(sqlite3_vfs*, void*);
00942   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
00943   int (*xSleep)(sqlite3_vfs*, int microseconds);
00944   int (*xCurrentTime)(sqlite3_vfs*, double*);
00945   int (*xGetLastError)(sqlite3_vfs*, int, char *);
00946   /*
00947   ** The methods above are in version 1 of the sqlite_vfs object
00948   ** definition.  Those that follow are added in version 2 or later
00949   */
00950   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
00951   /*
00952   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
00953   ** Those below are for version 3 and greater.
00954   */
00955   int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
00956   sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
00957   const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
00958   /*
00959   ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
00960   ** New fields may be appended in figure versions.  The iVersion
00961   ** value will increment whenever this happens. 
00962   */
00963 };
00964 
00965 /*
00966 ** CAPI3REF: Flags for the xAccess VFS method
00967 **
00968 ** These integer constants can be used as the third parameter to
00969 ** the xAccess method of an [sqlite3_vfs] object.  They determine
00970 ** what kind of permissions the xAccess method is looking for.
00971 ** With SQLITE_ACCESS_EXISTS, the xAccess method
00972 ** simply checks whether the file exists.
00973 ** With SQLITE_ACCESS_READWRITE, the xAccess method
00974 ** checks whether the named directory is both readable and writable
00975 ** (in other words, if files can be added, removed, and renamed within
00976 ** the directory).
00977 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
00978 ** [temp_store_directory pragma], though this could change in a future
00979 ** release of SQLite.
00980 ** With SQLITE_ACCESS_READ, the xAccess method
00981 ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
00982 ** currently unused, though it might be used in a future release of
00983 ** SQLite.
00984 */
00985 #define SQLITE_ACCESS_EXISTS    0
00986 #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
00987 #define SQLITE_ACCESS_READ      2   /* Unused */
00988 
00989 /*
00990 ** CAPI3REF: Flags for the xShmLock VFS method
00991 **
00992 ** These integer constants define the various locking operations
00993 ** allowed by the xShmLock method of [sqlite3_io_methods].  The
00994 ** following are the only legal combinations of flags to the
00995 ** xShmLock method:
00996 **
00997 ** <ul>
00998 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
00999 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
01000 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
01001 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
01002 ** </ul>
01003 **
01004 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
01005 ** was given no the corresponding lock.  
01006 **
01007 ** The xShmLock method can transition between unlocked and SHARED or
01008 ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
01009 ** and EXCLUSIVE.
01010 */
01011 #define SQLITE_SHM_UNLOCK       1
01012 #define SQLITE_SHM_LOCK         2
01013 #define SQLITE_SHM_SHARED       4
01014 #define SQLITE_SHM_EXCLUSIVE    8
01015 
01016 /*
01017 ** CAPI3REF: Maximum xShmLock index
01018 **
01019 ** The xShmLock method on [sqlite3_io_methods] may use values
01020 ** between 0 and this upper bound as its "offset" argument.
01021 ** The SQLite core will never attempt to acquire or release a
01022 ** lock outside of this range
01023 */
01024 #define SQLITE_SHM_NLOCK        8
01025 
01026 
01027 /*
01028 ** CAPI3REF: Initialize The SQLite Library
01029 **
01030 ** ^The sqlite3_initialize() routine initializes the
01031 ** SQLite library.  ^The sqlite3_shutdown() routine
01032 ** deallocates any resources that were allocated by sqlite3_initialize().
01033 ** These routines are designed to aid in process initialization and
01034 ** shutdown on embedded systems.  Workstation applications using
01035 ** SQLite normally do not need to invoke either of these routines.
01036 **
01037 ** A call to sqlite3_initialize() is an "effective" call if it is
01038 ** the first time sqlite3_initialize() is invoked during the lifetime of
01039 ** the process, or if it is the first time sqlite3_initialize() is invoked
01040 ** following a call to sqlite3_shutdown().  ^(Only an effective call
01041 ** of sqlite3_initialize() does any initialization.  All other calls
01042 ** are harmless no-ops.)^
01043 **
01044 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
01045 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
01046 ** an effective call to sqlite3_shutdown() does any deinitialization.
01047 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
01048 **
01049 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
01050 ** is not.  The sqlite3_shutdown() interface must only be called from a
01051 ** single thread.  All open [database connections] must be closed and all
01052 ** other SQLite resources must be deallocated prior to invoking
01053 ** sqlite3_shutdown().
01054 **
01055 ** Among other things, ^sqlite3_initialize() will invoke
01056 ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
01057 ** will invoke sqlite3_os_end().
01058 **
01059 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
01060 ** ^If for some reason, sqlite3_initialize() is unable to initialize
01061 ** the library (perhaps it is unable to allocate a needed resource such
01062 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
01063 **
01064 ** ^The sqlite3_initialize() routine is called internally by many other
01065 ** SQLite interfaces so that an application usually does not need to
01066 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
01067 ** calls sqlite3_initialize() so the SQLite library will be automatically
01068 ** initialized when [sqlite3_open()] is called if it has not be initialized
01069 ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
01070 ** compile-time option, then the automatic calls to sqlite3_initialize()
01071 ** are omitted and the application must call sqlite3_initialize() directly
01072 ** prior to using any other SQLite interface.  For maximum portability,
01073 ** it is recommended that applications always invoke sqlite3_initialize()
01074 ** directly prior to using any other SQLite interface.  Future releases
01075 ** of SQLite may require this.  In other words, the behavior exhibited
01076 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
01077 ** default behavior in some future release of SQLite.
01078 **
01079 ** The sqlite3_os_init() routine does operating-system specific
01080 ** initialization of the SQLite library.  The sqlite3_os_end()
01081 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
01082 ** performed by these routines include allocation or deallocation
01083 ** of static resources, initialization of global variables,
01084 ** setting up a default [sqlite3_vfs] module, or setting up
01085 ** a default configuration using [sqlite3_config()].
01086 **
01087 ** The application should never invoke either sqlite3_os_init()
01088 ** or sqlite3_os_end() directly.  The application should only invoke
01089 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
01090 ** interface is called automatically by sqlite3_initialize() and
01091 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
01092 ** implementations for sqlite3_os_init() and sqlite3_os_end()
01093 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
01094 ** When [custom builds | built for other platforms]
01095 ** (using the [SQLITE_OS_OTHER=1] compile-time
01096 ** option) the application must supply a suitable implementation for
01097 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
01098 ** implementation of sqlite3_os_init() or sqlite3_os_end()
01099 ** must return [SQLITE_OK] on success and some other [error code] upon
01100 ** failure.
01101 */
01102 SQLITE_API int sqlite3_initialize(void);
01103 SQLITE_API int sqlite3_shutdown(void);
01104 SQLITE_API int sqlite3_os_init(void);
01105 SQLITE_API int sqlite3_os_end(void);
01106 
01107 /*
01108 ** CAPI3REF: Configuring The SQLite Library
01109 **
01110 ** The sqlite3_config() interface is used to make global configuration
01111 ** changes to SQLite in order to tune SQLite to the specific needs of
01112 ** the application.  The default configuration is recommended for most
01113 ** applications and so this routine is usually not necessary.  It is
01114 ** provided to support rare applications with unusual needs.
01115 **
01116 ** The sqlite3_config() interface is not threadsafe.  The application
01117 ** must insure that no other SQLite interfaces are invoked by other
01118 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
01119 ** may only be invoked prior to library initialization using
01120 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
01121 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
01122 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
01123 ** Note, however, that ^sqlite3_config() can be called as part of the
01124 ** implementation of an application-defined [sqlite3_os_init()].
01125 **
01126 ** The first argument to sqlite3_config() is an integer
01127 ** [configuration option] that determines
01128 ** what property of SQLite is to be configured.  Subsequent arguments
01129 ** vary depending on the [configuration option]
01130 ** in the first argument.
01131 **
01132 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
01133 ** ^If the option is unknown or SQLite is unable to set the option
01134 ** then this routine returns a non-zero [error code].
01135 */
01136 SQLITE_API int sqlite3_config(int, ...);
01137 
01138 /*
01139 ** CAPI3REF: Configure database connections
01140 **
01141 ** The sqlite3_db_config() interface is used to make configuration
01142 ** changes to a [database connection].  The interface is similar to
01143 ** [sqlite3_config()] except that the changes apply to a single
01144 ** [database connection] (specified in the first argument).
01145 **
01146 ** The second argument to sqlite3_db_config(D,V,...)  is the
01147 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 
01148 ** that indicates what aspect of the [database connection] is being configured.
01149 ** Subsequent arguments vary depending on the configuration verb.
01150 **
01151 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
01152 ** the call is considered successful.
01153 */
01154 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
01155 
01156 /*
01157 ** CAPI3REF: Memory Allocation Routines
01158 **
01159 ** An instance of this object defines the interface between SQLite
01160 ** and low-level memory allocation routines.
01161 **
01162 ** This object is used in only one place in the SQLite interface.
01163 ** A pointer to an instance of this object is the argument to
01164 ** [sqlite3_config()] when the configuration option is
01165 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].  
01166 ** By creating an instance of this object
01167 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
01168 ** during configuration, an application can specify an alternative
01169 ** memory allocation subsystem for SQLite to use for all of its
01170 ** dynamic memory needs.
01171 **
01172 ** Note that SQLite comes with several [built-in memory allocators]
01173 ** that are perfectly adequate for the overwhelming majority of applications
01174 ** and that this object is only useful to a tiny minority of applications
01175 ** with specialized memory allocation requirements.  This object is
01176 ** also used during testing of SQLite in order to specify an alternative
01177 ** memory allocator that simulates memory out-of-memory conditions in
01178 ** order to verify that SQLite recovers gracefully from such
01179 ** conditions.
01180 **
01181 ** The xMalloc and xFree methods must work like the
01182 ** malloc() and free() functions from the standard C library.
01183 ** The xRealloc method must work like realloc() from the standard C library
01184 ** with the exception that if the second argument to xRealloc is zero,
01185 ** xRealloc must be a no-op - it must not perform any allocation or
01186 ** deallocation.  ^SQLite guarantees that the second argument to
01187 ** xRealloc is always a value returned by a prior call to xRoundup.
01188 ** And so in cases where xRoundup always returns a positive number,
01189 ** xRealloc can perform exactly as the standard library realloc() and
01190 ** still be in compliance with this specification.
01191 **
01192 ** xSize should return the allocated size of a memory allocation
01193 ** previously obtained from xMalloc or xRealloc.  The allocated size
01194 ** is always at least as big as the requested size but may be larger.
01195 **
01196 ** The xRoundup method returns what would be the allocated size of
01197 ** a memory allocation given a particular requested size.  Most memory
01198 ** allocators round up memory allocations at least to the next multiple
01199 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
01200 ** Every memory allocation request coming in through [sqlite3_malloc()]
01201 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0, 
01202 ** that causes the corresponding memory allocation to fail.
01203 **
01204 ** The xInit method initializes the memory allocator.  (For example,
01205 ** it might allocate any require mutexes or initialize internal data
01206 ** structures.  The xShutdown method is invoked (indirectly) by
01207 ** [sqlite3_shutdown()] and should deallocate any resources acquired
01208 ** by xInit.  The pAppData pointer is used as the only parameter to
01209 ** xInit and xShutdown.
01210 **
01211 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
01212 ** the xInit method, so the xInit method need not be threadsafe.  The
01213 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
01214 ** not need to be threadsafe either.  For all other methods, SQLite
01215 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
01216 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
01217 ** it is by default) and so the methods are automatically serialized.
01218 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
01219 ** methods must be threadsafe or else make their own arrangements for
01220 ** serialization.
01221 **
01222 ** SQLite will never invoke xInit() more than once without an intervening
01223 ** call to xShutdown().
01224 */
01225 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
01226 struct sqlite3_mem_methods {
01227   void *(*xMalloc)(int);         /* Memory allocation function */
01228   void (*xFree)(void*);          /* Free a prior allocation */
01229   void *(*xRealloc)(void*,int);  /* Resize an allocation */
01230   int (*xSize)(void*);           /* Return the size of an allocation */
01231   int (*xRoundup)(int);          /* Round up request size to allocation size */
01232   int (*xInit)(void*);           /* Initialize the memory allocator */
01233   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
01234   void *pAppData;                /* Argument to xInit() and xShutdown() */
01235 };
01236 
01237 /*
01238 ** CAPI3REF: Configuration Options
01239 ** KEYWORDS: {configuration option}
01240 **
01241 ** These constants are the available integer configuration options that
01242 ** can be passed as the first argument to the [sqlite3_config()] interface.
01243 **
01244 ** New configuration options may be added in future releases of SQLite.
01245 ** Existing configuration options might be discontinued.  Applications
01246 ** should check the return code from [sqlite3_config()] to make sure that
01247 ** the call worked.  The [sqlite3_config()] interface will return a
01248 ** non-zero [error code] if a discontinued or unsupported configuration option
01249 ** is invoked.
01250 **
01251 ** <dl>
01252 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
01253 ** <dd>There are no arguments to this option.  ^This option sets the
01254 ** [threading mode] to Single-thread.  In other words, it disables
01255 ** all mutexing and puts SQLite into a mode where it can only be used
01256 ** by a single thread.   ^If SQLite is compiled with
01257 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
01258 ** it is not possible to change the [threading mode] from its default
01259 ** value of Single-thread and so [sqlite3_config()] will return 
01260 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
01261 ** configuration option.</dd>
01262 **
01263 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
01264 ** <dd>There are no arguments to this option.  ^This option sets the
01265 ** [threading mode] to Multi-thread.  In other words, it disables
01266 ** mutexing on [database connection] and [prepared statement] objects.
01267 ** The application is responsible for serializing access to
01268 ** [database connections] and [prepared statements].  But other mutexes
01269 ** are enabled so that SQLite will be safe to use in a multi-threaded
01270 ** environment as long as no two threads attempt to use the same
01271 ** [database connection] at the same time.  ^If SQLite is compiled with
01272 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
01273 ** it is not possible to set the Multi-thread [threading mode] and
01274 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
01275 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
01276 **
01277 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
01278 ** <dd>There are no arguments to this option.  ^This option sets the
01279 ** [threading mode] to Serialized. In other words, this option enables
01280 ** all mutexes including the recursive
01281 ** mutexes on [database connection] and [prepared statement] objects.
01282 ** In this mode (which is the default when SQLite is compiled with
01283 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
01284 ** to [database connections] and [prepared statements] so that the
01285 ** application is free to use the same [database connection] or the
01286 ** same [prepared statement] in different threads at the same time.
01287 ** ^If SQLite is compiled with
01288 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
01289 ** it is not possible to set the Serialized [threading mode] and
01290 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
01291 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
01292 **
01293 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
01294 ** <dd> ^(This option takes a single argument which is a pointer to an
01295 ** instance of the [sqlite3_mem_methods] structure.  The argument specifies
01296 ** alternative low-level memory allocation routines to be used in place of
01297 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
01298 ** its own private copy of the content of the [sqlite3_mem_methods] structure
01299 ** before the [sqlite3_config()] call returns.</dd>
01300 **
01301 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
01302 ** <dd> ^(This option takes a single argument which is a pointer to an
01303 ** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
01304 ** structure is filled with the currently defined memory allocation routines.)^
01305 ** This option can be used to overload the default memory allocation
01306 ** routines with a wrapper that simulations memory allocation failure or
01307 ** tracks memory usage, for example. </dd>
01308 **
01309 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
01310 ** <dd> ^This option takes single argument of type int, interpreted as a 
01311 ** boolean, which enables or disables the collection of memory allocation 
01312 ** statistics. ^(When memory allocation statistics are disabled, the 
01313 ** following SQLite interfaces become non-operational:
01314 **   <ul>
01315 **   <li> [sqlite3_memory_used()]
01316 **   <li> [sqlite3_memory_highwater()]
01317 **   <li> [sqlite3_soft_heap_limit64()]
01318 **   <li> [sqlite3_status()]
01319 **   </ul>)^
01320 ** ^Memory allocation statistics are enabled by default unless SQLite is
01321 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
01322 ** allocation statistics are disabled by default.
01323 ** </dd>
01324 **
01325 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
01326 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
01327 ** scratch memory.  There are three arguments:  A pointer an 8-byte
01328 ** aligned memory buffer from which the scratch allocations will be
01329 ** drawn, the size of each scratch allocation (sz),
01330 ** and the maximum number of scratch allocations (N).  The sz
01331 ** argument must be a multiple of 16.
01332 ** The first argument must be a pointer to an 8-byte aligned buffer
01333 ** of at least sz*N bytes of memory.
01334 ** ^SQLite will use no more than two scratch buffers per thread.  So
01335 ** N should be set to twice the expected maximum number of threads.
01336 ** ^SQLite will never require a scratch buffer that is more than 6
01337 ** times the database page size. ^If SQLite needs needs additional
01338 ** scratch memory beyond what is provided by this configuration option, then 
01339 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
01340 **
01341 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
01342 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
01343 ** the database page cache with the default page cache implementation.  
01344 ** This configuration should not be used if an application-define page
01345 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
01346 ** There are three arguments to this option: A pointer to 8-byte aligned
01347 ** memory, the size of each page buffer (sz), and the number of pages (N).
01348 ** The sz argument should be the size of the largest database page
01349 ** (a power of two between 512 and 32768) plus a little extra for each
01350 ** page header.  ^The page header size is 20 to 40 bytes depending on
01351 ** the host architecture.  ^It is harmless, apart from the wasted memory,
01352 ** to make sz a little too large.  The first
01353 ** argument should point to an allocation of at least sz*N bytes of memory.
01354 ** ^SQLite will use the memory provided by the first argument to satisfy its
01355 ** memory needs for the first N pages that it adds to cache.  ^If additional
01356 ** page cache memory is needed beyond what is provided by this option, then
01357 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
01358 ** The pointer in the first argument must
01359 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
01360 ** will be undefined.</dd>
01361 **
01362 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
01363 ** <dd> ^This option specifies a static memory buffer that SQLite will use
01364 ** for all of its dynamic memory allocation needs beyond those provided
01365 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
01366 ** There are three arguments: An 8-byte aligned pointer to the memory,
01367 ** the number of bytes in the memory buffer, and the minimum allocation size.
01368 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
01369 ** to using its default memory allocator (the system malloc() implementation),
01370 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
01371 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
01372 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
01373 ** allocator is engaged to handle all of SQLites memory allocation needs.
01374 ** The first pointer (the memory pointer) must be aligned to an 8-byte
01375 ** boundary or subsequent behavior of SQLite will be undefined.
01376 ** The minimum allocation size is capped at 2^12. Reasonable values
01377 ** for the minimum allocation size are 2^5 through 2^8.</dd>
01378 **
01379 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
01380 ** <dd> ^(This option takes a single argument which is a pointer to an
01381 ** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
01382 ** alternative low-level mutex routines to be used in place
01383 ** the mutex routines built into SQLite.)^  ^SQLite makes a copy of the
01384 ** content of the [sqlite3_mutex_methods] structure before the call to
01385 ** [sqlite3_config()] returns. ^If SQLite is compiled with
01386 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
01387 ** the entire mutexing subsystem is omitted from the build and hence calls to
01388 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
01389 ** return [SQLITE_ERROR].</dd>
01390 **
01391 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
01392 ** <dd> ^(This option takes a single argument which is a pointer to an
01393 ** instance of the [sqlite3_mutex_methods] structure.  The
01394 ** [sqlite3_mutex_methods]
01395 ** structure is filled with the currently defined mutex routines.)^
01396 ** This option can be used to overload the default mutex allocation
01397 ** routines with a wrapper used to track mutex usage for performance
01398 ** profiling or testing, for example.   ^If SQLite is compiled with
01399 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
01400 ** the entire mutexing subsystem is omitted from the build and hence calls to
01401 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
01402 ** return [SQLITE_ERROR].</dd>
01403 **
01404 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
01405 ** <dd> ^(This option takes two arguments that determine the default
01406 ** memory allocation for the lookaside memory allocator on each
01407 ** [database connection].  The first argument is the
01408 ** size of each lookaside buffer slot and the second is the number of
01409 ** slots allocated to each database connection.)^  ^(This option sets the
01410 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
01411 ** verb to [sqlite3_db_config()] can be used to change the lookaside
01412 ** configuration on individual connections.)^ </dd>
01413 **
01414 ** [[SQLITE_CONFIG_PCACHE]] <dt>SQLITE_CONFIG_PCACHE</dt>
01415 ** <dd> ^(This option takes a single argument which is a pointer to
01416 ** an [sqlite3_pcache_methods] object.  This object specifies the interface
01417 ** to a custom page cache implementation.)^  ^SQLite makes a copy of the
01418 ** object and uses it for page cache memory allocations.</dd>
01419 **
01420 ** [[SQLITE_CONFIG_GETPCACHE]] <dt>SQLITE_CONFIG_GETPCACHE</dt>
01421 ** <dd> ^(This option takes a single argument which is a pointer to an
01422 ** [sqlite3_pcache_methods] object.  SQLite copies of the current
01423 ** page cache implementation into that object.)^ </dd>
01424 **
01425 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
01426 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
01427 ** function with a call signature of void(*)(void*,int,const char*), 
01428 ** and a pointer to void. ^If the function pointer is not NULL, it is
01429 ** invoked by [sqlite3_log()] to process each logging event.  ^If the
01430 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
01431 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
01432 ** passed through as the first parameter to the application-defined logger
01433 ** function whenever that function is invoked.  ^The second parameter to
01434 ** the logger function is a copy of the first parameter to the corresponding
01435 ** [sqlite3_log()] call and is intended to be a [result code] or an
01436 ** [extended result code].  ^The third parameter passed to the logger is
01437 ** log message after formatting via [sqlite3_snprintf()].
01438 ** The SQLite logging interface is not reentrant; the logger function
01439 ** supplied by the application must not invoke any SQLite interface.
01440 ** In a multi-threaded application, the application-defined logger
01441 ** function must be threadsafe. </dd>
01442 **
01443 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
01444 ** <dd> This option takes a single argument of type int. If non-zero, then
01445 ** URI handling is globally enabled. If the parameter is zero, then URI handling
01446 ** is globally disabled. If URI handling is globally enabled, all filenames
01447 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
01448 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
01449 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
01450 ** connection is opened. If it is globally disabled, filenames are
01451 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
01452 ** database connection is opened. By default, URI handling is globally
01453 ** disabled. The default value may be changed by compiling with the
01454 ** [SQLITE_USE_URI] symbol defined.
01455 ** </dl>
01456 */
01457 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
01458 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
01459 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
01460 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
01461 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
01462 #define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
01463 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
01464 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
01465 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
01466 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
01467 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
01468 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
01469 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
01470 #define SQLITE_CONFIG_PCACHE       14  /* sqlite3_pcache_methods* */
01471 #define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
01472 #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
01473 #define SQLITE_CONFIG_URI          17  /* int */
01474 
01475 /*
01476 ** CAPI3REF: Database Connection Configuration Options
01477 **
01478 ** These constants are the available integer configuration options that
01479 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
01480 **
01481 ** New configuration options may be added in future releases of SQLite.
01482 ** Existing configuration options might be discontinued.  Applications
01483 ** should check the return code from [sqlite3_db_config()] to make sure that
01484 ** the call worked.  ^The [sqlite3_db_config()] interface will return a
01485 ** non-zero [error code] if a discontinued or unsupported configuration option
01486 ** is invoked.
01487 **
01488 ** <dl>
01489 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
01490 ** <dd> ^This option takes three additional arguments that determine the 
01491 ** [lookaside memory allocator] configuration for the [database connection].
01492 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
01493 ** pointer to a memory buffer to use for lookaside memory.
01494 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
01495 ** may be NULL in which case SQLite will allocate the
01496 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
01497 ** size of each lookaside buffer slot.  ^The third argument is the number of
01498 ** slots.  The size of the buffer in the first argument must be greater than
01499 ** or equal to the product of the second and third arguments.  The buffer
01500 ** must be aligned to an 8-byte boundary.  ^If the second argument to
01501 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
01502 ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
01503 ** configuration for a database connection can only be changed when that
01504 ** connection is not currently using lookaside memory, or in other words
01505 ** when the "current value" returned by
01506 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
01507 ** Any attempt to change the lookaside memory configuration when lookaside
01508 ** memory is in use leaves the configuration unchanged and returns 
01509 ** [SQLITE_BUSY].)^</dd>
01510 **
01511 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
01512 ** <dd> ^This option is used to enable or disable the enforcement of
01513 ** [foreign key constraints].  There should be two additional arguments.
01514 ** The first argument is an integer which is 0 to disable FK enforcement,
01515 ** positive to enable FK enforcement or negative to leave FK enforcement
01516 ** unchanged.  The second parameter is a pointer to an integer into which
01517 ** is written 0 or 1 to indicate whether FK enforcement is off or on
01518 ** following this call.  The second parameter may be a NULL pointer, in
01519 ** which case the FK enforcement setting is not reported back. </dd>
01520 **
01521 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
01522 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
01523 ** There should be two additional arguments.
01524 ** The first argument is an integer which is 0 to disable triggers,
01525 ** positive to enable triggers or negative to leave the setting unchanged.
01526 ** The second parameter is a pointer to an integer into which
01527 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
01528 ** following this call.  The second parameter may be a NULL pointer, in
01529 ** which case the trigger setting is not reported back. </dd>
01530 **
01531 ** </dl>
01532 */
01533 #define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
01534 #define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
01535 #define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
01536 
01537 
01538 /*
01539 ** CAPI3REF: Enable Or Disable Extended Result Codes
01540 **
01541 ** ^The sqlite3_extended_result_codes() routine enables or disables the
01542 ** [extended result codes] feature of SQLite. ^The extended result
01543 ** codes are disabled by default for historical compatibility.
01544 */
01545 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
01546 
01547 /*
01548 ** CAPI3REF: Last Insert Rowid
01549 **
01550 ** ^Each entry in an SQLite table has a unique 64-bit signed
01551 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
01552 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
01553 ** names are not also used by explicitly declared columns. ^If
01554 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
01555 ** is another alias for the rowid.
01556 **
01557 ** ^This routine returns the [rowid] of the most recent
01558 ** successful [INSERT] into the database from the [database connection]
01559 ** in the first argument.  ^As of SQLite version 3.7.7, this routines
01560 ** records the last insert rowid of both ordinary tables and [virtual tables].
01561 ** ^If no successful [INSERT]s
01562 ** have ever occurred on that database connection, zero is returned.
01563 **
01564 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
01565 ** method, then this routine will return the [rowid] of the inserted
01566 ** row as long as the trigger or virtual table method is running.
01567 ** But once the trigger or virtual table method ends, the value returned 
01568 ** by this routine reverts to what it was before the trigger or virtual
01569 ** table method began.)^
01570 **
01571 ** ^An [INSERT] that fails due to a constraint violation is not a
01572 ** successful [INSERT] and does not change the value returned by this
01573 ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
01574 ** and INSERT OR ABORT make no changes to the return value of this
01575 ** routine when their insertion fails.  ^(When INSERT OR REPLACE
01576 ** encounters a constraint violation, it does not fail.  The
01577 ** INSERT continues to completion after deleting rows that caused
01578 ** the constraint problem so INSERT OR REPLACE will always change
01579 ** the return value of this interface.)^
01580 **
01581 ** ^For the purposes of this routine, an [INSERT] is considered to
01582 ** be successful even if it is subsequently rolled back.
01583 **
01584 ** This function is accessible to SQL statements via the
01585 ** [last_insert_rowid() SQL function].
01586 **
01587 ** If a separate thread performs a new [INSERT] on the same
01588 ** database connection while the [sqlite3_last_insert_rowid()]
01589 ** function is running and thus changes the last insert [rowid],
01590 ** then the value returned by [sqlite3_last_insert_rowid()] is
01591 ** unpredictable and might not equal either the old or the new
01592 ** last insert [rowid].
01593 */
01594 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
01595 
01596 /*
01597 ** CAPI3REF: Count The Number Of Rows Modified
01598 **
01599 ** ^This function returns the number of database rows that were changed
01600 ** or inserted or deleted by the most recently completed SQL statement
01601 ** on the [database connection] specified by the first parameter.
01602 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
01603 ** or [DELETE] statement are counted.  Auxiliary changes caused by
01604 ** triggers or [foreign key actions] are not counted.)^ Use the
01605 ** [sqlite3_total_changes()] function to find the total number of changes
01606 ** including changes caused by triggers and foreign key actions.
01607 **
01608 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
01609 ** are not counted.  Only real table changes are counted.
01610 **
01611 ** ^(A "row change" is a change to a single row of a single table
01612 ** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
01613 ** are changed as side effects of [REPLACE] constraint resolution,
01614 ** rollback, ABORT processing, [DROP TABLE], or by any other
01615 ** mechanisms do not count as direct row changes.)^
01616 **
01617 ** A "trigger context" is a scope of execution that begins and
01618 ** ends with the script of a [CREATE TRIGGER | trigger]. 
01619 ** Most SQL statements are
01620 ** evaluated outside of any trigger.  This is the "top level"
01621 ** trigger context.  If a trigger fires from the top level, a
01622 ** new trigger context is entered for the duration of that one
01623 ** trigger.  Subtriggers create subcontexts for their duration.
01624 **
01625 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
01626 ** not create a new trigger context.
01627 **
01628 ** ^This function returns the number of direct row changes in the
01629 ** most recent INSERT, UPDATE, or DELETE statement within the same
01630 ** trigger context.
01631 **
01632 ** ^Thus, when called from the top level, this function returns the
01633 ** number of changes in the most recent INSERT, UPDATE, or DELETE
01634 ** that also occurred at the top level.  ^(Within the body of a trigger,
01635 ** the sqlite3_changes() interface can be called to find the number of
01636 ** changes in the most recently completed INSERT, UPDATE, or DELETE
01637 ** statement within the body of the same trigger.
01638 ** However, the number returned does not include changes
01639 ** caused by subtriggers since those have their own context.)^
01640 **
01641 ** See also the [sqlite3_total_changes()] interface, the
01642 ** [count_changes pragma], and the [changes() SQL function].
01643 **
01644 ** If a separate thread makes changes on the same database connection
01645 ** while [sqlite3_changes()] is running then the value returned
01646 ** is unpredictable and not meaningful.
01647 */
01648 SQLITE_API int sqlite3_changes(sqlite3*);
01649 
01650 /*
01651 ** CAPI3REF: Total Number Of Rows Modified
01652 **
01653 ** ^This function returns the number of row changes caused by [INSERT],
01654 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
01655 ** ^(The count returned by sqlite3_total_changes() includes all changes
01656 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
01657 ** [foreign key actions]. However,
01658 ** the count does not include changes used to implement [REPLACE] constraints,
01659 ** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The
01660 ** count does not include rows of views that fire an [INSTEAD OF trigger],
01661 ** though if the INSTEAD OF trigger makes changes of its own, those changes 
01662 ** are counted.)^
01663 ** ^The sqlite3_total_changes() function counts the changes as soon as
01664 ** the statement that makes them is completed (when the statement handle
01665 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
01666 **
01667 ** See also the [sqlite3_changes()] interface, the
01668 ** [count_changes pragma], and the [total_changes() SQL function].
01669 **
01670 ** If a separate thread makes changes on the same database connection
01671 ** while [sqlite3_total_changes()] is running then the value
01672 ** returned is unpredictable and not meaningful.
01673 */
01674 SQLITE_API int sqlite3_total_changes(sqlite3*);
01675 
01676 /*
01677 ** CAPI3REF: Interrupt A Long-Running Query
01678 **
01679 ** ^This function causes any pending database operation to abort and
01680 ** return at its earliest opportunity. This routine is typically
01681 ** called in response to a user action such as pressing "Cancel"
01682 ** or Ctrl-C where the user wants a long query operation to halt
01683 ** immediately.
01684 **
01685 ** ^It is safe to call this routine from a thread different from the
01686 ** thread that is currently running the database operation.  But it
01687 ** is not safe to call this routine with a [database connection] that
01688 ** is closed or might close before sqlite3_interrupt() returns.
01689 **
01690 ** ^If an SQL operation is very nearly finished at the time when
01691 ** sqlite3_interrupt() is called, then it might not have an opportunity
01692 ** to be interrupted and might continue to completion.
01693 **
01694 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
01695 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
01696 ** that is inside an explicit transaction, then the entire transaction
01697 ** will be rolled back automatically.
01698 **
01699 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
01700 ** SQL statements on [database connection] D complete.  ^Any new SQL statements
01701 ** that are started after the sqlite3_interrupt() call and before the 
01702 ** running statements reaches zero are interrupted as if they had been
01703 ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
01704 ** that are started after the running statement count reaches zero are
01705 ** not effected by the sqlite3_interrupt().
01706 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
01707 ** SQL statements is a no-op and has no effect on SQL statements
01708 ** that are started after the sqlite3_interrupt() call returns.
01709 **
01710 ** If the database connection closes while [sqlite3_interrupt()]
01711 ** is running then bad things will likely happen.
01712 */
01713 SQLITE_API void sqlite3_interrupt(sqlite3*);
01714 
01715 /*
01716 ** CAPI3REF: Determine If An SQL Statement Is Complete
01717 **
01718 ** These routines are useful during command-line input to determine if the
01719 ** currently entered text seems to form a complete SQL statement or
01720 ** if additional input is needed before sending the text into
01721 ** SQLite for parsing.  ^These routines return 1 if the input string
01722 ** appears to be a complete SQL statement.  ^A statement is judged to be
01723 ** complete if it ends with a semicolon token and is not a prefix of a
01724 ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
01725 ** string literals or quoted identifier names or comments are not
01726 ** independent tokens (they are part of the token in which they are
01727 ** embedded) and thus do not count as a statement terminator.  ^Whitespace
01728 ** and comments that follow the final semicolon are ignored.
01729 **
01730 ** ^These routines return 0 if the statement is incomplete.  ^If a
01731 ** memory allocation fails, then SQLITE_NOMEM is returned.
01732 **
01733 ** ^These routines do not parse the SQL statements thus
01734 ** will not detect syntactically incorrect SQL.
01735 **
01736 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 
01737 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
01738 ** automatically by sqlite3_complete16().  If that initialization fails,
01739 ** then the return value from sqlite3_complete16() will be non-zero
01740 ** regardless of whether or not the input SQL is complete.)^
01741 **
01742 ** The input to [sqlite3_complete()] must be a zero-terminated
01743 ** UTF-8 string.
01744 **
01745 ** The input to [sqlite3_complete16()] must be a zero-terminated
01746 ** UTF-16 string in native byte order.
01747 */
01748 SQLITE_API int sqlite3_complete(const char *sql);
01749 SQLITE_API int sqlite3_complete16(const void *sql);
01750 
01751 /*
01752 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
01753 **
01754 ** ^This routine sets a callback function that might be invoked whenever
01755 ** an attempt is made to open a database table that another thread
01756 ** or process has locked.
01757 **
01758 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
01759 ** is returned immediately upon encountering the lock.  ^If the busy callback
01760 ** is not NULL, then the callback might be invoked with two arguments.
01761 **
01762 ** ^The first argument to the busy handler is a copy of the void* pointer which
01763 ** is the third argument to sqlite3_busy_handler().  ^The second argument to
01764 ** the busy handler callback is the number of times that the busy handler has
01765 ** been invoked for this locking event.  ^If the
01766 ** busy callback returns 0, then no additional attempts are made to
01767 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
01768 ** ^If the callback returns non-zero, then another attempt
01769 ** is made to open the database for reading and the cycle repeats.
01770 **
01771 ** The presence of a busy handler does not guarantee that it will be invoked
01772 ** when there is lock contention. ^If SQLite determines that invoking the busy
01773 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
01774 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
01775 ** Consider a scenario where one process is holding a read lock that
01776 ** it is trying to promote to a reserved lock and
01777 ** a second process is holding a reserved lock that it is trying
01778 ** to promote to an exclusive lock.  The first process cannot proceed
01779 ** because it is blocked by the second and the second process cannot
01780 ** proceed because it is blocked by the first.  If both processes
01781 ** invoke the busy handlers, neither will make any progress.  Therefore,
01782 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
01783 ** will induce the first process to release its read lock and allow
01784 ** the second process to proceed.
01785 **
01786 ** ^The default busy callback is NULL.
01787 **
01788 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
01789 ** when SQLite is in the middle of a large transaction where all the
01790 ** changes will not fit into the in-memory cache.  SQLite will
01791 ** already hold a RESERVED lock on the database file, but it needs
01792 ** to promote this lock to EXCLUSIVE so that it can spill cache
01793 ** pages into the database file without harm to concurrent
01794 ** readers.  ^If it is unable to promote the lock, then the in-memory
01795 ** cache will be left in an inconsistent state and so the error
01796 ** code is promoted from the relatively benign [SQLITE_BUSY] to
01797 ** the more severe [SQLITE_IOERR_BLOCKED].  ^This error code promotion
01798 ** forces an automatic rollback of the changes.  See the
01799 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
01800 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
01801 ** this is important.
01802 **
01803 ** ^(There can only be a single busy handler defined for each
01804 ** [database connection].  Setting a new busy handler clears any
01805 ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
01806 ** will also set or clear the busy handler.
01807 **
01808 ** The busy callback should not take any actions which modify the
01809 ** database connection that invoked the busy handler.  Any such actions
01810 ** result in undefined behavior.
01811 ** 
01812 ** A busy handler must not close the database connection
01813 ** or [prepared statement] that invoked the busy handler.
01814 */
01815 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
01816 
01817 /*
01818 ** CAPI3REF: Set A Busy Timeout
01819 **
01820 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
01821 ** for a specified amount of time when a table is locked.  ^The handler
01822 ** will sleep multiple times until at least "ms" milliseconds of sleeping
01823 ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
01824 ** the handler returns 0 which causes [sqlite3_step()] to return
01825 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
01826 **
01827 ** ^Calling this routine with an argument less than or equal to zero
01828 ** turns off all busy handlers.
01829 **
01830 ** ^(There can only be a single busy handler for a particular
01831 ** [database connection] any any given moment.  If another busy handler
01832 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
01833 ** this routine, that other busy handler is cleared.)^
01834 */
01835 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
01836 
01837 /*
01838 ** CAPI3REF: Convenience Routines For Running Queries
01839 **
01840 ** This is a legacy interface that is preserved for backwards compatibility.
01841 ** Use of this interface is not recommended.
01842 **
01843 ** Definition: A <b>result table</b> is memory data structure created by the
01844 ** [sqlite3_get_table()] interface.  A result table records the
01845 ** complete query results from one or more queries.
01846 **
01847 ** The table conceptually has a number of rows and columns.  But
01848 ** these numbers are not part of the result table itself.  These
01849 ** numbers are obtained separately.  Let N be the number of rows
01850 ** and M be the number of columns.
01851 **
01852 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
01853 ** There are (N+1)*M elements in the array.  The first M pointers point
01854 ** to zero-terminated strings that  contain the names of the columns.
01855 ** The remaining entries all point to query results.  NULL values result
01856 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
01857 ** string representation as returned by [sqlite3_column_text()].
01858 **
01859 ** A result table might consist of one or more memory allocations.
01860 ** It is not safe to pass a result table directly to [sqlite3_free()].
01861 ** A result table should be deallocated using [sqlite3_free_table()].
01862 **
01863 ** ^(As an example of the result table format, suppose a query result
01864 ** is as follows:
01865 **
01866 ** <blockquote><pre>
01867 **        Name        | Age
01868 **        -----------------------
01869 **        Alice       | 43
01870 **        Bob         | 28
01871 **        Cindy       | 21
01872 ** </pre></blockquote>
01873 **
01874 ** There are two column (M==2) and three rows (N==3).  Thus the
01875 ** result table has 8 entries.  Suppose the result table is stored
01876 ** in an array names azResult.  Then azResult holds this content:
01877 **
01878 ** <blockquote><pre>
01879 **        azResult&#91;0] = "Name";
01880 **        azResult&#91;1] = "Age";
01881 **        azResult&#91;2] = "Alice";
01882 **        azResult&#91;3] = "43";
01883 **        azResult&#91;4] = "Bob";
01884 **        azResult&#91;5] = "28";
01885 **        azResult&#91;6] = "Cindy";
01886 **        azResult&#91;7] = "21";
01887 ** </pre></blockquote>)^
01888 **
01889 ** ^The sqlite3_get_table() function evaluates one or more
01890 ** semicolon-separated SQL statements in the zero-terminated UTF-8
01891 ** string of its 2nd parameter and returns a result table to the
01892 ** pointer given in its 3rd parameter.
01893 **
01894 ** After the application has finished with the result from sqlite3_get_table(),
01895 ** it must pass the result table pointer to sqlite3_free_table() in order to
01896 ** release the memory that was malloced.  Because of the way the
01897 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
01898 ** function must not try to call [sqlite3_free()] directly.  Only
01899 ** [sqlite3_free_table()] is able to release the memory properly and safely.
01900 **
01901 ** The sqlite3_get_table() interface is implemented as a wrapper around
01902 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
01903 ** to any internal data structures of SQLite.  It uses only the public
01904 ** interface defined here.  As a consequence, errors that occur in the
01905 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
01906 ** reflected in subsequent calls to [sqlite3_errcode()] or
01907 ** [sqlite3_errmsg()].
01908 */
01909 SQLITE_API int sqlite3_get_table(
01910   sqlite3 *db,          /* An open database */
01911   const char *zSql,     /* SQL to be evaluated */
01912   char ***pazResult,    /* Results of the query */
01913   int *pnRow,           /* Number of result rows written here */
01914   int *pnColumn,        /* Number of result columns written here */
01915   char **pzErrmsg       /* Error msg written here */
01916 );
01917 SQLITE_API void sqlite3_free_table(char **result);
01918 
01919 /*
01920 ** CAPI3REF: Formatted String Printing Functions
01921 **
01922 ** These routines are work-alikes of the "printf()" family of functions
01923 ** from the standard C library.
01924 **
01925 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
01926 ** results into memory obtained from [sqlite3_malloc()].
01927 ** The strings returned by these two routines should be
01928 ** released by [sqlite3_free()].  ^Both routines return a
01929 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
01930 ** memory to hold the resulting string.
01931 **
01932 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
01933 ** the standard C library.  The result is written into the
01934 ** buffer supplied as the second parameter whose size is given by
01935 ** the first parameter. Note that the order of the
01936 ** first two parameters is reversed from snprintf().)^  This is an
01937 ** historical accident that cannot be fixed without breaking
01938 ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
01939 ** returns a pointer to its buffer instead of the number of
01940 ** characters actually written into the buffer.)^  We admit that
01941 ** the number of characters written would be a more useful return
01942 ** value but we cannot change the implementation of sqlite3_snprintf()
01943 ** now without breaking compatibility.
01944 **
01945 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
01946 ** guarantees that the buffer is always zero-terminated.  ^The first
01947 ** parameter "n" is the total size of the buffer, including space for
01948 ** the zero terminator.  So the longest string that can be completely
01949 ** written will be n-1 characters.
01950 **
01951 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
01952 **
01953 ** These routines all implement some additional formatting
01954 ** options that are useful for constructing SQL statements.
01955 ** All of the usual printf() formatting options apply.  In addition, there
01956 ** is are "%q", "%Q", and "%z" options.
01957 **
01958 ** ^(The %q option works like %s in that it substitutes a null-terminated
01959 ** string from the argument list.  But %q also doubles every '\'' character.
01960 ** %q is designed for use inside a string literal.)^  By doubling each '\''
01961 ** character it escapes that character and allows it to be inserted into
01962 ** the string.
01963 **
01964 ** For example, assume the string variable zText contains text as follows:
01965 **
01966 ** <blockquote><pre>
01967 **  char *zText = "It's a happy day!";
01968 ** </pre></blockquote>
01969 **
01970 ** One can use this text in an SQL statement as follows:
01971 **
01972 ** <blockquote><pre>
01973 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
01974 **  sqlite3_exec(db, zSQL, 0, 0, 0);
01975 **  sqlite3_free(zSQL);
01976 ** </pre></blockquote>
01977 **
01978 ** Because the %q format string is used, the '\'' character in zText
01979 ** is escaped and the SQL generated is as follows:
01980 **
01981 ** <blockquote><pre>
01982 **  INSERT INTO table1 VALUES('It''s a happy day!')
01983 ** </pre></blockquote>
01984 **
01985 ** This is correct.  Had we used %s instead of %q, the generated SQL
01986 ** would have looked like this:
01987 **
01988 ** <blockquote><pre>
01989 **  INSERT INTO table1 VALUES('It's a happy day!');
01990 ** </pre></blockquote>
01991 **
01992 ** This second example is an SQL syntax error.  As a general rule you should
01993 ** always use %q instead of %s when inserting text into a string literal.
01994 **
01995 ** ^(The %Q option works like %q except it also adds single quotes around
01996 ** the outside of the total string.  Additionally, if the parameter in the
01997 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
01998 ** single quotes).)^  So, for example, one could say:
01999 **
02000 ** <blockquote><pre>
02001 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
02002 **  sqlite3_exec(db, zSQL, 0, 0, 0);
02003 **  sqlite3_free(zSQL);
02004 ** </pre></blockquote>
02005 **
02006 ** The code above will render a correct SQL statement in the zSQL
02007 ** variable even if the zText variable is a NULL pointer.
02008 **
02009 ** ^(The "%z" formatting option works like "%s" but with the
02010 ** addition that after the string has been read and copied into
02011 ** the result, [sqlite3_free()] is called on the input string.)^
02012 */
02013 SQLITE_API char *sqlite3_mprintf(const char*,...);
02014 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
02015 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
02016 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
02017 
02018 /*
02019 ** CAPI3REF: Memory Allocation Subsystem
02020 **
02021 ** The SQLite core uses these three routines for all of its own
02022 ** internal memory allocation needs. "Core" in the previous sentence
02023 ** does not include operating-system specific VFS implementation.  The
02024 ** Windows VFS uses native malloc() and free() for some operations.
02025 **
02026 ** ^The sqlite3_malloc() routine returns a pointer to a block
02027 ** of memory at least N bytes in length, where N is the parameter.
02028 ** ^If sqlite3_malloc() is unable to obtain sufficient free
02029 ** memory, it returns a NULL pointer.  ^If the parameter N to
02030 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
02031 ** a NULL pointer.
02032 **
02033 ** ^Calling sqlite3_free() with a pointer previously returned
02034 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
02035 ** that it might be reused.  ^The sqlite3_free() routine is
02036 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
02037 ** to sqlite3_free() is harmless.  After being freed, memory
02038 ** should neither be read nor written.  Even reading previously freed
02039 ** memory might result in a segmentation fault or other severe error.
02040 ** Memory corruption, a segmentation fault, or other severe error
02041 ** might result if sqlite3_free() is called with a non-NULL pointer that
02042 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
02043 **
02044 ** ^(The sqlite3_realloc() interface attempts to resize a
02045 ** prior memory allocation to be at least N bytes, where N is the
02046 ** second parameter.  The memory allocation to be resized is the first
02047 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
02048 ** is a NULL pointer then its behavior is identical to calling
02049 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
02050 ** ^If the second parameter to sqlite3_realloc() is zero or
02051 ** negative then the behavior is exactly the same as calling
02052 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
02053 ** ^sqlite3_realloc() returns a pointer to a memory allocation
02054 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
02055 ** ^If M is the size of the prior allocation, then min(N,M) bytes
02056 ** of the prior allocation are copied into the beginning of buffer returned
02057 ** by sqlite3_realloc() and the prior allocation is freed.
02058 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
02059 ** is not freed.
02060 **
02061 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
02062 ** is always aligned to at least an 8 byte boundary, or to a
02063 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
02064 ** option is used.
02065 **
02066 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
02067 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
02068 ** implementation of these routines to be omitted.  That capability
02069 ** is no longer provided.  Only built-in memory allocators can be used.
02070 **
02071 ** The Windows OS interface layer calls
02072 ** the system malloc() and free() directly when converting
02073 ** filenames between the UTF-8 encoding used by SQLite
02074 ** and whatever filename encoding is used by the particular Windows
02075 ** installation.  Memory allocation errors are detected, but
02076 ** they are reported back as [SQLITE_CANTOPEN] or
02077 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
02078 **
02079 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
02080 ** must be either NULL or else pointers obtained from a prior
02081 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
02082 ** not yet been released.
02083 **
02084 ** The application must not read or write any part of
02085 ** a block of memory after it has been released using
02086 ** [sqlite3_free()] or [sqlite3_realloc()].
02087 */
02088 SQLITE_API void *sqlite3_malloc(int);
02089 SQLITE_API void *sqlite3_realloc(void*, int);
02090 SQLITE_API void sqlite3_free(void*);
02091 
02092 /*
02093 ** CAPI3REF: Memory Allocator Statistics
02094 **
02095 ** SQLite provides these two interfaces for reporting on the status
02096 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
02097 ** routines, which form the built-in memory allocation subsystem.
02098 **
02099 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
02100 ** of memory currently outstanding (malloced but not freed).
02101 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
02102 ** value of [sqlite3_memory_used()] since the high-water mark
02103 ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
02104 ** [sqlite3_memory_highwater()] include any overhead
02105 ** added by SQLite in its implementation of [sqlite3_malloc()],
02106 ** but not overhead added by the any underlying system library
02107 ** routines that [sqlite3_malloc()] may call.
02108 **
02109 ** ^The memory high-water mark is reset to the current value of
02110 ** [sqlite3_memory_used()] if and only if the parameter to
02111 ** [sqlite3_memory_highwater()] is true.  ^The value returned
02112 ** by [sqlite3_memory_highwater(1)] is the high-water mark
02113 ** prior to the reset.
02114 */
02115 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
02116 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
02117 
02118 /*
02119 ** CAPI3REF: Pseudo-Random Number Generator
02120 **
02121 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
02122 ** select random [ROWID | ROWIDs] when inserting new records into a table that
02123 ** already uses the largest possible [ROWID].  The PRNG is also used for
02124 ** the build-in random() and randomblob() SQL functions.  This interface allows
02125 ** applications to access the same PRNG for other purposes.
02126 **
02127 ** ^A call to this routine stores N bytes of randomness into buffer P.
02128 **
02129 ** ^The first time this routine is invoked (either internally or by
02130 ** the application) the PRNG is seeded using randomness obtained
02131 ** from the xRandomness method of the default [sqlite3_vfs] object.
02132 ** ^On all subsequent invocations, the pseudo-randomness is generated
02133 ** internally and without recourse to the [sqlite3_vfs] xRandomness
02134 ** method.
02135 */
02136 SQLITE_API void sqlite3_randomness(int N, void *P);
02137 
02138 /*
02139 ** CAPI3REF: Compile-Time Authorization Callbacks
02140 **
02141 ** ^This routine registers an authorizer callback with a particular
02142 ** [database connection], supplied in the first argument.
02143 ** ^The authorizer callback is invoked as SQL statements are being compiled
02144 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
02145 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
02146 ** points during the compilation process, as logic is being created
02147 ** to perform various actions, the authorizer callback is invoked to
02148 ** see if those actions are allowed.  ^The authorizer callback should
02149 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
02150 ** specific action but allow the SQL statement to continue to be
02151 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
02152 ** rejected with an error.  ^If the authorizer callback returns
02153 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
02154 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
02155 ** the authorizer will fail with an error message.
02156 **
02157 ** When the callback returns [SQLITE_OK], that means the operation
02158 ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
02159 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
02160 ** authorizer will fail with an error message explaining that
02161 ** access is denied. 
02162 **
02163 ** ^The first parameter to the authorizer callback is a copy of the third
02164 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
02165 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
02166 ** the particular action to be authorized. ^The third through sixth parameters
02167 ** to the callback are zero-terminated strings that contain additional
02168 ** details about the action to be authorized.
02169 **
02170 ** ^If the action code is [SQLITE_READ]
02171 ** and the callback returns [SQLITE_IGNORE] then the
02172 ** [prepared statement] statement is constructed to substitute
02173 ** a NULL value in place of the table column that would have
02174 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
02175 ** return can be used to deny an untrusted user access to individual
02176 ** columns of a table.
02177 ** ^If the action code is [SQLITE_DELETE] and the callback returns
02178 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
02179 ** [truncate optimization] is disabled and all rows are deleted individually.
02180 **
02181 ** An authorizer is used when [sqlite3_prepare | preparing]
02182 ** SQL statements from an untrusted source, to ensure that the SQL statements
02183 ** do not try to access data they are not allowed to see, or that they do not
02184 ** try to execute malicious statements that damage the database.  For
02185 ** example, an application may allow a user to enter arbitrary
02186 ** SQL queries for evaluation by a database.  But the application does
02187 ** not want the user to be able to make arbitrary changes to the
02188 ** database.  An authorizer could then be put in place while the
02189 ** user-entered SQL is being [sqlite3_prepare | prepared] that
02190 ** disallows everything except [SELECT] statements.
02191 **
02192 ** Applications that need to process SQL from untrusted sources
02193 ** might also consider lowering resource limits using [sqlite3_limit()]
02194 ** and limiting database size using the [max_page_count] [PRAGMA]
02195 ** in addition to using an authorizer.
02196 **
02197 ** ^(Only a single authorizer can be in place on a database connection
02198 ** at a time.  Each call to sqlite3_set_authorizer overrides the
02199 ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
02200 ** The authorizer is disabled by default.
02201 **
02202 ** The authorizer callback must not do anything that will modify
02203 ** the database connection that invoked the authorizer callback.
02204 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
02205 ** database connections for the meaning of "modify" in this paragraph.
02206 **
02207 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
02208 ** statement might be re-prepared during [sqlite3_step()] due to a 
02209 ** schema change.  Hence, the application should ensure that the
02210 ** correct authorizer callback remains in place during the [sqlite3_step()].
02211 **
02212 ** ^Note that the authorizer callback is invoked only during
02213 ** [sqlite3_prepare()] or its variants.  Authorization is not
02214 ** performed during statement evaluation in [sqlite3_step()], unless
02215 ** as stated in the previous paragraph, sqlite3_step() invokes
02216 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
02217 */
02218 SQLITE_API int sqlite3_set_authorizer(
02219   sqlite3*,
02220   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
02221   void *pUserData
02222 );
02223 
02224 /*
02225 ** CAPI3REF: Authorizer Return Codes
02226 **
02227 ** The [sqlite3_set_authorizer | authorizer callback function] must
02228 ** return either [SQLITE_OK] or one of these two constants in order
02229 ** to signal SQLite whether or not the action is permitted.  See the
02230 ** [sqlite3_set_authorizer | authorizer documentation] for additional
02231 ** information.
02232 **
02233 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
02234 ** from the [sqlite3_vtab_on_conflict()] interface.
02235 */
02236 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
02237 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
02238 
02239 /*
02240 ** CAPI3REF: Authorizer Action Codes
02241 **
02242 ** The [sqlite3_set_authorizer()] interface registers a callback function
02243 ** that is invoked to authorize certain SQL statement actions.  The
02244 ** second parameter to the callback is an integer code that specifies
02245 ** what action is being authorized.  These are the integer action codes that
02246 ** the authorizer callback may be passed.
02247 **
02248 ** These action code values signify what kind of operation is to be
02249 ** authorized.  The 3rd and 4th parameters to the authorization
02250 ** callback function will be parameters or NULL depending on which of these
02251 ** codes is used as the second parameter.  ^(The 5th parameter to the
02252 ** authorizer callback is the name of the database ("main", "temp",
02253 ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
02254 ** is the name of the inner-most trigger or view that is responsible for
02255 ** the access attempt or NULL if this access attempt is directly from
02256 ** top-level SQL code.
02257 */
02258 /******************************************* 3rd ************ 4th ***********/
02259 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
02260 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
02261 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
02262 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
02263 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
02264 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
02265 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
02266 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
02267 #define SQLITE_DELETE                9   /* Table Name      NULL            */
02268 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
02269 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
02270 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
02271 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
02272 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
02273 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
02274 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
02275 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
02276 #define SQLITE_INSERT               18   /* Table Name      NULL            */
02277 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
02278 #define SQLITE_READ                 20   /* Table Name      Column Name     */
02279 #define SQLITE_SELECT               21   /* NULL            NULL            */
02280 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
02281 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
02282 #define SQLITE_ATTACH               24   /* Filename        NULL            */
02283 #define SQLITE_DETACH               25   /* Database Name   NULL            */
02284 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
02285 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
02286 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
02287 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
02288 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
02289 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
02290 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
02291 #define SQLITE_COPY                  0   /* No longer used */
02292 
02293 /*
02294 ** CAPI3REF: Tracing And Profiling Functions
02295 **
02296 ** These routines register callback functions that can be used for
02297 ** tracing and profiling the execution of SQL statements.
02298 **
02299 ** ^The callback function registered by sqlite3_trace() is invoked at
02300 ** various times when an SQL statement is being run by [sqlite3_step()].
02301 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
02302 ** SQL statement text as the statement first begins executing.
02303 ** ^(Additional sqlite3_trace() callbacks might occur
02304 ** as each triggered subprogram is entered.  The callbacks for triggers
02305 ** contain a UTF-8 SQL comment that identifies the trigger.)^
02306 **
02307 ** ^The callback function registered by sqlite3_profile() is invoked
02308 ** as each SQL statement finishes.  ^The profile callback contains
02309 ** the original statement text and an estimate of wall-clock time
02310 ** of how long that statement took to run.  ^The profile callback
02311 ** time is in units of nanoseconds, however the current implementation
02312 ** is only capable of millisecond resolution so the six least significant
02313 ** digits in the time are meaningless.  Future versions of SQLite
02314 ** might provide greater resolution on the profiler callback.  The
02315 ** sqlite3_profile() function is considered experimental and is
02316 ** subject to change in future versions of SQLite.
02317 */
02318 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
02319 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
02320    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
02321 
02322 /*
02323 ** CAPI3REF: Query Progress Callbacks
02324 **
02325 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
02326 ** function X to be invoked periodically during long running calls to
02327 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
02328 ** database connection D.  An example use for this
02329 ** interface is to keep a GUI updated during a large query.
02330 **
02331 ** ^The parameter P is passed through as the only parameter to the 
02332 ** callback function X.  ^The parameter N is the number of 
02333 ** [virtual machine instructions] that are evaluated between successive
02334 ** invocations of the callback X.
02335 **
02336 ** ^Only a single progress handler may be defined at one time per
02337 ** [database connection]; setting a new progress handler cancels the
02338 ** old one.  ^Setting parameter X to NULL disables the progress handler.
02339 ** ^The progress handler is also disabled by setting N to a value less
02340 ** than 1.
02341 **
02342 ** ^If the progress callback returns non-zero, the operation is
02343 ** interrupted.  This feature can be used to implement a
02344 ** "Cancel" button on a GUI progress dialog box.
02345 **
02346 ** The progress handler callback must not do anything that will modify
02347 ** the database connection that invoked the progress handler.
02348 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
02349 ** database connections for the meaning of "modify" in this paragraph.
02350 **
02351 */
02352 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
02353 
02354 /*
02355 ** CAPI3REF: Opening A New Database Connection
02356 **
02357 ** ^These routines open an SQLite database file as specified by the 
02358 ** filename argument. ^The filename argument is interpreted as UTF-8 for
02359 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
02360 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
02361 ** returned in *ppDb, even if an error occurs.  The only exception is that
02362 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
02363 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
02364 ** object.)^ ^(If the database is opened (and/or created) successfully, then
02365 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
02366 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
02367 ** an English language description of the error following a failure of any
02368 ** of the sqlite3_open() routines.
02369 **
02370 ** ^The default encoding for the database will be UTF-8 if
02371 ** sqlite3_open() or sqlite3_open_v2() is called and
02372 ** UTF-16 in the native byte order if sqlite3_open16() is used.
02373 **
02374 ** Whether or not an error occurs when it is opened, resources
02375 ** associated with the [database connection] handle should be released by
02376 ** passing it to [sqlite3_close()] when it is no longer required.
02377 **
02378 ** The sqlite3_open_v2() interface works like sqlite3_open()
02379 ** except that it accepts two additional parameters for additional control
02380 ** over the new database connection.  ^(The flags parameter to
02381 ** sqlite3_open_v2() can take one of
02382 ** the following three values, optionally combined with the 
02383 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
02384 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
02385 **
02386 ** <dl>
02387 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
02388 ** <dd>The database is opened in read-only mode.  If the database does not
02389 ** already exist, an error is returned.</dd>)^
02390 **
02391 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
02392 ** <dd>The database is opened for reading and writing if possible, or reading
02393 ** only if the file is write protected by the operating system.  In either
02394 ** case the database must already exist, otherwise an error is returned.</dd>)^
02395 **
02396 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
02397 ** <dd>The database is opened for reading and writing, and is created if
02398 ** it does not already exist. This is the behavior that is always used for
02399 ** sqlite3_open() and sqlite3_open16().</dd>)^
02400 ** </dl>
02401 **
02402 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
02403 ** combinations shown above optionally combined with other
02404 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
02405 ** then the behavior is undefined.
02406 **
02407 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
02408 ** opens in the multi-thread [threading mode] as long as the single-thread
02409 ** mode has not been set at compile-time or start-time.  ^If the
02410 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
02411 ** in the serialized [threading mode] unless single-thread was
02412 ** previously selected at compile-time or start-time.
02413 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
02414 ** eligible to use [shared cache mode], regardless of whether or not shared
02415 ** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
02416 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
02417 ** participate in [shared cache mode] even if it is enabled.
02418 **
02419 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
02420 ** [sqlite3_vfs] object that defines the operating system interface that
02421 ** the new database connection should use.  ^If the fourth parameter is
02422 ** a NULL pointer then the default [sqlite3_vfs] object is used.
02423 **
02424 ** ^If the filename is ":memory:", then a private, temporary in-memory database
02425 ** is created for the connection.  ^This in-memory database will vanish when
02426 ** the database connection is closed.  Future versions of SQLite might
02427 ** make use of additional special filenames that begin with the ":" character.
02428 ** It is recommended that when a database filename actually does begin with
02429 ** a ":" character you should prefix the filename with a pathname such as
02430 ** "./" to avoid ambiguity.
02431 **
02432 ** ^If the filename is an empty string, then a private, temporary
02433 ** on-disk database will be created.  ^This private database will be
02434 ** automatically deleted as soon as the database connection is closed.
02435 **
02436 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
02437 **
02438 ** ^If [URI filename] interpretation is enabled, and the filename argument
02439 ** begins with "file:", then the filename is interpreted as a URI. ^URI
02440 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
02441 ** set in the fourth argument to sqlite3_open_v2(), or if it has
02442 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
02443 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
02444 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
02445 ** by default, but future releases of SQLite might enable URI filename
02446 ** interpretation by default.  See "[URI filenames]" for additional
02447 ** information.
02448 **
02449 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
02450 ** authority, then it must be either an empty string or the string 
02451 ** "localhost". ^If the authority is not an empty string or "localhost", an 
02452 ** error is returned to the caller. ^The fragment component of a URI, if 
02453 ** present, is ignored.
02454 **
02455 ** ^SQLite uses the path component of the URI as the name of the disk file
02456 ** which contains the database. ^If the path begins with a '/' character, 
02457 ** then it is interpreted as an absolute path. ^If the path does not begin 
02458 ** with a '/' (meaning that the authority section is omitted from the URI)
02459 ** then the path is interpreted as a relative path. 
02460 ** ^On windows, the first component of an absolute path 
02461 ** is a drive specification (e.g. "C:").
02462 **
02463 ** [[core URI query parameters]]
02464 ** The query component of a URI may contain parameters that are interpreted
02465 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
02466 ** SQLite interprets the following three query parameters:
02467 **
02468 ** <ul>
02469 **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
02470 **     a VFS object that provides the operating system interface that should
02471 **     be used to access the database file on disk. ^If this option is set to
02472 **     an empty string the default VFS object is used. ^Specifying an unknown
02473 **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
02474 **     present, then the VFS specified by the option takes precedence over
02475 **     the value passed as the fourth parameter to sqlite3_open_v2().
02476 **
02477 **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or
02478 **     "rwc". Attempting to set it to any other value is an error)^. 
02479 **     ^If "ro" is specified, then the database is opened for read-only 
02480 **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 
02481 **     third argument to sqlite3_prepare_v2(). ^If the mode option is set to 
02482 **     "rw", then the database is opened for read-write (but not create) 
02483 **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 
02484 **     been set. ^Value "rwc" is equivalent to setting both 
02485 **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 
02486 **     used, it is an error to specify a value for the mode parameter that is 
02487 **     less restrictive than that specified by the flags passed as the third 
02488 **     parameter.
02489 **
02490 **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
02491 **     "private". ^Setting it to "shared" is equivalent to setting the
02492 **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
02493 **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is 
02494 **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
02495 **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
02496 **     a URI filename, its value overrides any behaviour requested by setting
02497 **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
02498 ** </ul>
02499 **
02500 ** ^Specifying an unknown parameter in the query component of a URI is not an
02501 ** error.  Future versions of SQLite might understand additional query
02502 ** parameters.  See "[query parameters with special meaning to SQLite]" for
02503 ** additional information.
02504 **
02505 ** [[URI filename examples]] <h3>URI filename examples</h3>
02506 **
02507 ** <table border="1" align=center cellpadding=5>
02508 ** <tr><th> URI filenames <th> Results
02509 ** <tr><td> file:data.db <td> 
02510 **          Open the file "data.db" in the current directory.
02511 ** <tr><td> file:/home/fred/data.db<br>
02512 **          file:///home/fred/data.db <br> 
02513 **          file://localhost/home/fred/data.db <br> <td> 
02514 **          Open the database file "/home/fred/data.db".
02515 ** <tr><td> file://darkstar/home/fred/data.db <td> 
02516 **          An error. "darkstar" is not a recognized authority.
02517 ** <tr><td style="white-space:nowrap"> 
02518 **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
02519 **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
02520 **          C:. Note that the %20 escaping in this example is not strictly 
02521 **          necessary - space characters can be used literally
02522 **          in URI filenames.
02523 ** <tr><td> file:data.db?mode=ro&cache=private <td> 
02524 **          Open file "data.db" in the current directory for read-only access.
02525 **          Regardless of whether or not shared-cache mode is enabled by
02526 **          default, use a private cache.
02527 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
02528 **          Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
02529 ** <tr><td> file:data.db?mode=readonly <td> 
02530 **          An error. "readonly" is not a valid option for the "mode" parameter.
02531 ** </table>
02532 **
02533 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
02534 ** query components of a URI. A hexadecimal escape sequence consists of a
02535 ** percent sign - "%" - followed by exactly two hexadecimal digits 
02536 ** specifying an octet value. ^Before the path or query components of a
02537 ** URI filename are interpreted, they are encoded using UTF-8 and all 
02538 ** hexadecimal escape sequences replaced by a single byte containing the
02539 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
02540 ** the results are undefined.
02541 **
02542 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
02543 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
02544 ** codepage is currently defined.  Filenames containing international
02545 ** characters must be converted to UTF-8 prior to passing them into
02546 ** sqlite3_open() or sqlite3_open_v2().
02547 */
02548 SQLITE_API int sqlite3_open(
02549   const char *filename,   /* Database filename (UTF-8) */
02550   sqlite3 **ppDb          /* OUT: SQLite db handle */
02551 );
02552 SQLITE_API int sqlite3_open16(
02553   const void *filename,   /* Database filename (UTF-16) */
02554   sqlite3 **ppDb          /* OUT: SQLite db handle */
02555 );
02556 SQLITE_API int sqlite3_open_v2(
02557   const char *filename,   /* Database filename (UTF-8) */
02558   sqlite3 **ppDb,         /* OUT: SQLite db handle */
02559   int flags,              /* Flags */
02560   const char *zVfs        /* Name of VFS module to use */
02561 );
02562 
02563 /*
02564 ** CAPI3REF: Obtain Values For URI Parameters
02565 **
02566 ** This is a utility routine, useful to VFS implementations, that checks
02567 ** to see if a database file was a URI that contained a specific query 
02568 ** parameter, and if so obtains the value of the query parameter.
02569 **
02570 ** The zFilename argument is the filename pointer passed into the xOpen()
02571 ** method of a VFS implementation.  The zParam argument is the name of the
02572 ** query parameter we seek.  This routine returns the value of the zParam
02573 ** parameter if it exists.  If the parameter does not exist, this routine
02574 ** returns a NULL pointer.
02575 **
02576 ** If the zFilename argument to this function is not a pointer that SQLite
02577 ** passed into the xOpen VFS method, then the behavior of this routine
02578 ** is undefined and probably undesirable.
02579 */
02580 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
02581 
02582 
02583 /*
02584 ** CAPI3REF: Error Codes And Messages
02585 **
02586 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
02587 ** [extended result code] for the most recent failed sqlite3_* API call
02588 ** associated with a [database connection]. If a prior API call failed
02589 ** but the most recent API call succeeded, the return value from
02590 ** sqlite3_errcode() is undefined.  ^The sqlite3_extended_errcode()
02591 ** interface is the same except that it always returns the 
02592 ** [extended result code] even when extended result codes are
02593 ** disabled.
02594 **
02595 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
02596 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
02597 ** ^(Memory to hold the error message string is managed internally.
02598 ** The application does not need to worry about freeing the result.
02599 ** However, the error string might be overwritten or deallocated by
02600 ** subsequent calls to other SQLite interface functions.)^
02601 **
02602 ** When the serialized [threading mode] is in use, it might be the
02603 ** case that a second error occurs on a separate thread in between
02604 ** the time of the first error and the call to these interfaces.
02605 ** When that happens, the second error will be reported since these
02606 ** interfaces always report the most recent result.  To avoid
02607 ** this, each thread can obtain exclusive use of the [database connection] D
02608 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
02609 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
02610 ** all calls to the interfaces listed here are completed.
02611 **
02612 ** If an interface fails with SQLITE_MISUSE, that means the interface
02613 ** was invoked incorrectly by the application.  In that case, the
02614 ** error code and message may or may not be set.
02615 */
02616 SQLITE_API int sqlite3_errcode(sqlite3 *db);
02617 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
02618 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
02619 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
02620 
02621 /*
02622 ** CAPI3REF: SQL Statement Object
02623 ** KEYWORDS: {prepared statement} {prepared statements}
02624 **
02625 ** An instance of this object represents a single SQL statement.
02626 ** This object is variously known as a "prepared statement" or a
02627 ** "compiled SQL statement" or simply as a "statement".
02628 **
02629 ** The life of a statement object goes something like this:
02630 **
02631 ** <ol>
02632 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
02633 **      function.
02634 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
02635 **      interfaces.
02636 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
02637 ** <li> Reset the statement using [sqlite3_reset()] then go back
02638 **      to step 2.  Do this zero or more times.
02639 ** <li> Destroy the object using [sqlite3_finalize()].
02640 ** </ol>
02641 **
02642 ** Refer to documentation on individual methods above for additional
02643 ** information.
02644 */
02645 typedef struct sqlite3_stmt sqlite3_stmt;
02646 
02647 /*
02648 ** CAPI3REF: Run-time Limits
02649 **
02650 ** ^(This interface allows the size of various constructs to be limited
02651 ** on a connection by connection basis.  The first parameter is the
02652 ** [database connection] whose limit is to be set or queried.  The
02653 ** second parameter is one of the [limit categories] that define a
02654 ** class of constructs to be size limited.  The third parameter is the
02655 ** new limit for that construct.)^
02656 **
02657 ** ^If the new limit is a negative number, the limit is unchanged.
02658 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 
02659 ** [limits | hard upper bound]
02660 ** set at compile-time by a C preprocessor macro called
02661 ** [limits | SQLITE_MAX_<i>NAME</i>].
02662 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
02663 ** ^Attempts to increase a limit above its hard upper bound are
02664 ** silently truncated to the hard upper bound.
02665 **
02666 ** ^Regardless of whether or not the limit was changed, the 
02667 ** [sqlite3_limit()] interface returns the prior value of the limit.
02668 ** ^Hence, to find the current value of a limit without changing it,
02669 ** simply invoke this interface with the third parameter set to -1.
02670 **
02671 ** Run-time limits are intended for use in applications that manage
02672 ** both their own internal database and also databases that are controlled
02673 ** by untrusted external sources.  An example application might be a
02674 ** web browser that has its own databases for storing history and
02675 ** separate databases controlled by JavaScript applications downloaded
02676 ** off the Internet.  The internal databases can be given the
02677 ** large, default limits.  Databases managed by external sources can
02678 ** be given much smaller limits designed to prevent a denial of service
02679 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
02680 ** interface to further control untrusted SQL.  The size of the database
02681 ** created by an untrusted script can be contained using the
02682 ** [max_page_count] [PRAGMA].
02683 **
02684 ** New run-time limit categories may be added in future releases.
02685 */
02686 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
02687 
02688 /*
02689 ** CAPI3REF: Run-Time Limit Categories
02690 ** KEYWORDS: {limit category} {*limit categories}
02691 **
02692 ** These constants define various performance limits
02693 ** that can be lowered at run-time using [sqlite3_limit()].
02694 ** The synopsis of the meanings of the various limits is shown below.
02695 ** Additional information is available at [limits | Limits in SQLite].
02696 **
02697 ** <dl>
02698 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
02699 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
02700 **
02701 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
02702 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
02703 **
02704 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
02705 ** <dd>The maximum number of columns in a table definition or in the
02706 ** result set of a [SELECT] or the maximum number of columns in an index
02707 ** or in an ORDER BY or GROUP BY clause.</dd>)^
02708 **
02709 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
02710 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
02711 **
02712 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
02713 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
02714 **
02715 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
02716 ** <dd>The maximum number of instructions in a virtual machine program
02717 ** used to implement an SQL statement.  This limit is not currently
02718 ** enforced, though that might be added in some future release of
02719 ** SQLite.</dd>)^
02720 **
02721 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
02722 ** <dd>The maximum number of arguments on a function.</dd>)^
02723 **
02724 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
02725 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
02726 **
02727 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
02728 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
02729 ** <dd>The maximum length of the pattern argument to the [LIKE] or
02730 ** [GLOB] operators.</dd>)^
02731 **
02732 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
02733 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
02734 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
02735 **
02736 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
02737 ** <dd>The maximum depth of recursion for triggers.</dd>)^
02738 ** </dl>
02739 */
02740 #define SQLITE_LIMIT_LENGTH                    0
02741 #define SQLITE_LIMIT_SQL_LENGTH                1
02742 #define SQLITE_LIMIT_COLUMN                    2
02743 #define SQLITE_LIMIT_EXPR_DEPTH                3
02744 #define SQLITE_LIMIT_COMPOUND_SELECT           4
02745 #define SQLITE_LIMIT_VDBE_OP                   5
02746 #define SQLITE_LIMIT_FUNCTION_ARG              6
02747 #define SQLITE_LIMIT_ATTACHED                  7
02748 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
02749 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
02750 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
02751 
02752 /*
02753 ** CAPI3REF: Compiling An SQL Statement
02754 ** KEYWORDS: {SQL statement compiler}
02755 **
02756 ** To execute an SQL query, it must first be compiled into a byte-code
02757 ** program using one of these routines.
02758 **
02759 ** The first argument, "db", is a [database connection] obtained from a
02760 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
02761 ** [sqlite3_open16()].  The database connection must not have been closed.
02762 **
02763 ** The second argument, "zSql", is the statement to be compiled, encoded
02764 ** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
02765 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
02766 ** use UTF-16.
02767 **
02768 ** ^If the nByte argument is less than zero, then zSql is read up to the
02769 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
02770 ** number of  bytes read from zSql.  ^When nByte is non-negative, the
02771 ** zSql string ends at either the first '\000' or '\u0000' character or
02772 ** the nByte-th byte, whichever comes first. If the caller knows
02773 ** that the supplied string is nul-terminated, then there is a small
02774 ** performance advantage to be gained by passing an nByte parameter that
02775 ** is equal to the number of bytes in the input string <i>including</i>
02776 ** the nul-terminator bytes.
02777 **
02778 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
02779 ** past the end of the first SQL statement in zSql.  These routines only
02780 ** compile the first statement in zSql, so *pzTail is left pointing to
02781 ** what remains uncompiled.
02782 **
02783 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
02784 ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
02785 ** to NULL.  ^If the input text contains no SQL (if the input is an empty
02786 ** string or a comment) then *ppStmt is set to NULL.
02787 ** The calling procedure is responsible for deleting the compiled
02788 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
02789 ** ppStmt may not be NULL.
02790 **
02791 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
02792 ** otherwise an [error code] is returned.
02793 **
02794 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
02795 ** recommended for all new programs. The two older interfaces are retained
02796 ** for backwards compatibility, but their use is discouraged.
02797 ** ^In the "v2" interfaces, the prepared statement
02798 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
02799 ** original SQL text. This causes the [sqlite3_step()] interface to
02800 ** behave differently in three ways:
02801 **
02802 ** <ol>
02803 ** <li>
02804 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
02805 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
02806 ** statement and try to run it again.
02807 ** </li>
02808 **
02809 ** <li>
02810 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
02811 ** [error codes] or [extended error codes].  ^The legacy behavior was that
02812 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
02813 ** and the application would have to make a second call to [sqlite3_reset()]
02814 ** in order to find the underlying cause of the problem. With the "v2" prepare
02815 ** interfaces, the underlying reason for the error is returned immediately.
02816 ** </li>
02817 **
02818 ** <li>
02819 ** ^If the specific value bound to [parameter | host parameter] in the 
02820 ** WHERE clause might influence the choice of query plan for a statement,
02821 ** then the statement will be automatically recompiled, as if there had been 
02822 ** a schema change, on the first  [sqlite3_step()] call following any change
02823 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 
02824 ** ^The specific value of WHERE-clause [parameter] might influence the 
02825 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
02826 ** or [GLOB] operator or if the parameter is compared to an indexed column
02827 ** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled.
02828 ** the 
02829 ** </li>
02830 ** </ol>
02831 */
02832 SQLITE_API int sqlite3_prepare(
02833   sqlite3 *db,            /* Database handle */
02834   const char *zSql,       /* SQL statement, UTF-8 encoded */
02835   int nByte,              /* Maximum length of zSql in bytes. */
02836   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
02837   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
02838 );
02839 SQLITE_API int sqlite3_prepare_v2(
02840   sqlite3 *db,            /* Database handle */
02841   const char *zSql,       /* SQL statement, UTF-8 encoded */
02842   int nByte,              /* Maximum length of zSql in bytes. */
02843   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
02844   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
02845 );
02846 SQLITE_API int sqlite3_prepare16(
02847   sqlite3 *db,            /* Database handle */
02848   const void *zSql,       /* SQL statement, UTF-16 encoded */
02849   int nByte,              /* Maximum length of zSql in bytes. */
02850   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
02851   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
02852 );
02853 SQLITE_API int sqlite3_prepare16_v2(
02854   sqlite3 *db,            /* Database handle */
02855   const void *zSql,       /* SQL statement, UTF-16 encoded */
02856   int nByte,              /* Maximum length of zSql in bytes. */
02857   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
02858   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
02859 );
02860 
02861 /*
02862 ** CAPI3REF: Retrieving Statement SQL
02863 **
02864 ** ^This interface can be used to retrieve a saved copy of the original
02865 ** SQL text used to create a [prepared statement] if that statement was
02866 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
02867 */
02868 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
02869 
02870 /*
02871 ** CAPI3REF: Determine If An SQL Statement Writes The Database
02872 **
02873 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
02874 ** and only if the [prepared statement] X makes no direct changes to
02875 ** the content of the database file.
02876 **
02877 ** Note that [application-defined SQL functions] or
02878 ** [virtual tables] might change the database indirectly as a side effect.  
02879 ** ^(For example, if an application defines a function "eval()" that 
02880 ** calls [sqlite3_exec()], then the following SQL statement would
02881 ** change the database file through side-effects:
02882 **
02883 ** <blockquote><pre>
02884 **    SELECT eval('DELETE FROM t1') FROM t2;
02885 ** </pre></blockquote>
02886 **
02887 ** But because the [SELECT] statement does not change the database file
02888 ** directly, sqlite3_stmt_readonly() would still return true.)^
02889 **
02890 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
02891 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
02892 ** since the statements themselves do not actually modify the database but
02893 ** rather they control the timing of when other statements modify the 
02894 ** database.  ^The [ATTACH] and [DETACH] statements also cause
02895 ** sqlite3_stmt_readonly() to return true since, while those statements
02896 ** change the configuration of a database connection, they do not make 
02897 ** changes to the content of the database files on disk.
02898 */
02899 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
02900 
02901 /*
02902 ** CAPI3REF: Dynamically Typed Value Object
02903 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
02904 **
02905 ** SQLite uses the sqlite3_value object to represent all values
02906 ** that can be stored in a database table. SQLite uses dynamic typing
02907 ** for the values it stores.  ^Values stored in sqlite3_value objects
02908 ** can be integers, floating point values, strings, BLOBs, or NULL.
02909 **
02910 ** An sqlite3_value object may be either "protected" or "unprotected".
02911 ** Some interfaces require a protected sqlite3_value.  Other interfaces
02912 ** will accept either a protected or an unprotected sqlite3_value.
02913 ** Every interface that accepts sqlite3_value arguments specifies
02914 ** whether or not it requires a protected sqlite3_value.
02915 **
02916 ** The terms "protected" and "unprotected" refer to whether or not
02917 ** a mutex is held.  An internal mutex is held for a protected
02918 ** sqlite3_value object but no mutex is held for an unprotected
02919 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
02920 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
02921 ** or if SQLite is run in one of reduced mutex modes 
02922 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
02923 ** then there is no distinction between protected and unprotected
02924 ** sqlite3_value objects and they can be used interchangeably.  However,
02925 ** for maximum code portability it is recommended that applications
02926 ** still make the distinction between protected and unprotected
02927 ** sqlite3_value objects even when not strictly required.
02928 **
02929 ** ^The sqlite3_value objects that are passed as parameters into the
02930 ** implementation of [application-defined SQL functions] are protected.
02931 ** ^The sqlite3_value object returned by
02932 ** [sqlite3_column_value()] is unprotected.
02933 ** Unprotected sqlite3_value objects may only be used with
02934 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
02935 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
02936 ** interfaces require protected sqlite3_value objects.
02937 */
02938 typedef struct Mem sqlite3_value;
02939 
02940 /*
02941 ** CAPI3REF: SQL Function Context Object
02942 **
02943 ** The context in which an SQL function executes is stored in an
02944 ** sqlite3_context object.  ^A pointer to an sqlite3_context object
02945 ** is always first parameter to [application-defined SQL functions].
02946 ** The application-defined SQL function implementation will pass this
02947 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
02948 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
02949 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
02950 ** and/or [sqlite3_set_auxdata()].
02951 */
02952 typedef struct sqlite3_context sqlite3_context;
02953 
02954 /*
02955 ** CAPI3REF: Binding Values To Prepared Statements
02956 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
02957 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
02958 **
02959 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
02960 ** literals may be replaced by a [parameter] that matches one of following
02961 ** templates:
02962 **
02963 ** <ul>
02964 ** <li>  ?
02965 ** <li>  ?NNN
02966 ** <li>  :VVV
02967 ** <li>  @VVV
02968 ** <li>  $VVV
02969 ** </ul>
02970 **
02971 ** In the templates above, NNN represents an integer literal,
02972 ** and VVV represents an alphanumeric identifier.)^  ^The values of these
02973 ** parameters (also called "host parameter names" or "SQL parameters")
02974 ** can be set using the sqlite3_bind_*() routines defined here.
02975 **
02976 ** ^The first argument to the sqlite3_bind_*() routines is always
02977 ** a pointer to the [sqlite3_stmt] object returned from
02978 ** [sqlite3_prepare_v2()] or its variants.
02979 **
02980 ** ^The second argument is the index of the SQL parameter to be set.
02981 ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
02982 ** SQL parameter is used more than once, second and subsequent
02983 ** occurrences have the same index as the first occurrence.
02984 ** ^The index for named parameters can be looked up using the
02985 ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
02986 ** for "?NNN" parameters is the value of NNN.
02987 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
02988 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
02989 **
02990 ** ^The third argument is the value to bind to the parameter.
02991 **
02992 ** ^(In those routines that have a fourth argument, its value is the
02993 ** number of bytes in the parameter.  To be clear: the value is the
02994 ** number of <u>bytes</u> in the value, not the number of characters.)^
02995 ** ^If the fourth parameter is negative, the length of the string is
02996 ** the number of bytes up to the first zero terminator.
02997 **
02998 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
02999 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
03000 ** string after SQLite has finished with it.  ^The destructor is called
03001 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
03002 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.  
03003 ** ^If the fifth argument is
03004 ** the special value [SQLITE_STATIC], then SQLite assumes that the
03005 ** information is in static, unmanaged space and does not need to be freed.
03006 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
03007 ** SQLite makes its own private copy of the data immediately, before
03008 ** the sqlite3_bind_*() routine returns.
03009 **
03010 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
03011 ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
03012 ** (just an integer to hold its size) while it is being processed.
03013 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
03014 ** content is later written using
03015 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
03016 ** ^A negative value for the zeroblob results in a zero-length BLOB.
03017 **
03018 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
03019 ** for the [prepared statement] or with a prepared statement for which
03020 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
03021 ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
03022 ** routine is passed a [prepared statement] that has been finalized, the
03023 ** result is undefined and probably harmful.
03024 **
03025 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
03026 ** ^Unbound parameters are interpreted as NULL.
03027 **
03028 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
03029 ** [error code] if anything goes wrong.
03030 ** ^[SQLITE_RANGE] is returned if the parameter
03031 ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
03032 **
03033 ** See also: [sqlite3_bind_parameter_count()],
03034 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
03035 */
03036 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
03037 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
03038 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
03039 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
03040 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
03041 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
03042 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
03043 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
03044 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
03045 
03046 /*
03047 ** CAPI3REF: Number Of SQL Parameters
03048 **
03049 ** ^This routine can be used to find the number of [SQL parameters]
03050 ** in a [prepared statement].  SQL parameters are tokens of the
03051 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
03052 ** placeholders for values that are [sqlite3_bind_blob | bound]
03053 ** to the parameters at a later time.
03054 **
03055 ** ^(This routine actually returns the index of the largest (rightmost)
03056 ** parameter. For all forms except ?NNN, this will correspond to the
03057 ** number of unique parameters.  If parameters of the ?NNN form are used,
03058 ** there may be gaps in the list.)^
03059 **
03060 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
03061 ** [sqlite3_bind_parameter_name()], and
03062 ** [sqlite3_bind_parameter_index()].
03063 */
03064 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
03065 
03066 /*
03067 ** CAPI3REF: Name Of A Host Parameter
03068 **
03069 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
03070 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
03071 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
03072 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
03073 ** respectively.
03074 ** In other words, the initial ":" or "$" or "@" or "?"
03075 ** is included as part of the name.)^
03076 ** ^Parameters of the form "?" without a following integer have no name
03077 ** and are referred to as "nameless" or "anonymous parameters".
03078 **
03079 ** ^The first host parameter has an index of 1, not 0.
03080 **
03081 ** ^If the value N is out of range or if the N-th parameter is
03082 ** nameless, then NULL is returned.  ^The returned string is
03083 ** always in UTF-8 encoding even if the named parameter was
03084 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
03085 ** [sqlite3_prepare16_v2()].
03086 **
03087 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
03088 ** [sqlite3_bind_parameter_count()], and
03089 ** [sqlite3_bind_parameter_index()].
03090 */
03091 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
03092 
03093 /*
03094 ** CAPI3REF: Index Of A Parameter With A Given Name
03095 **
03096 ** ^Return the index of an SQL parameter given its name.  ^The
03097 ** index value returned is suitable for use as the second
03098 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
03099 ** is returned if no matching parameter is found.  ^The parameter
03100 ** name must be given in UTF-8 even if the original statement
03101 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
03102 **
03103 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
03104 ** [sqlite3_bind_parameter_count()], and
03105 ** [sqlite3_bind_parameter_index()].
03106 */
03107 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
03108 
03109 /*
03110 ** CAPI3REF: Reset All Bindings On A Prepared Statement
03111 **
03112 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
03113 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
03114 ** ^Use this routine to reset all host parameters to NULL.
03115 */
03116 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
03117 
03118 /*
03119 ** CAPI3REF: Number Of Columns In A Result Set
03120 **
03121 ** ^Return the number of columns in the result set returned by the
03122 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
03123 ** statement that does not return data (for example an [UPDATE]).
03124 **
03125 ** See also: [sqlite3_data_count()]
03126 */
03127 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
03128 
03129 /*
03130 ** CAPI3REF: Column Names In A Result Set
03131 **
03132 ** ^These routines return the name assigned to a particular column
03133 ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
03134 ** interface returns a pointer to a zero-terminated UTF-8 string
03135 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
03136 ** UTF-16 string.  ^The first parameter is the [prepared statement]
03137 ** that implements the [SELECT] statement. ^The second parameter is the
03138 ** column number.  ^The leftmost column is number 0.
03139 **
03140 ** ^The returned string pointer is valid until either the [prepared statement]
03141 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
03142 ** reprepared by the first call to [sqlite3_step()] for a particular run
03143 ** or until the next call to
03144 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
03145 **
03146 ** ^If sqlite3_malloc() fails during the processing of either routine
03147 ** (for example during a conversion from UTF-8 to UTF-16) then a
03148 ** NULL pointer is returned.
03149 **
03150 ** ^The name of a result column is the value of the "AS" clause for
03151 ** that column, if there is an AS clause.  If there is no AS clause
03152 ** then the name of the column is unspecified and may change from
03153 ** one release of SQLite to the next.
03154 */
03155 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
03156 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
03157 
03158 /*
03159 ** CAPI3REF: Source Of Data In A Query Result
03160 **
03161 ** ^These routines provide a means to determine the database, table, and
03162 ** table column that is the origin of a particular result column in
03163 ** [SELECT] statement.
03164 ** ^The name of the database or table or column can be returned as
03165 ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
03166 ** the database name, the _table_ routines return the table name, and
03167 ** the origin_ routines return the column name.
03168 ** ^The returned string is valid until the [prepared statement] is destroyed
03169 ** using [sqlite3_finalize()] or until the statement is automatically
03170 ** reprepared by the first call to [sqlite3_step()] for a particular run
03171 ** or until the same information is requested
03172 ** again in a different encoding.
03173 **
03174 ** ^The names returned are the original un-aliased names of the
03175 ** database, table, and column.
03176 **
03177 ** ^The first argument to these interfaces is a [prepared statement].
03178 ** ^These functions return information about the Nth result column returned by
03179 ** the statement, where N is the second function argument.
03180 ** ^The left-most column is column 0 for these routines.
03181 **
03182 ** ^If the Nth column returned by the statement is an expression or
03183 ** subquery and is not a column value, then all of these functions return
03184 ** NULL.  ^These routine might also return NULL if a memory allocation error
03185 ** occurs.  ^Otherwise, they return the name of the attached database, table,
03186 ** or column that query result column was extracted from.
03187 **
03188 ** ^As with all other SQLite APIs, those whose names end with "16" return
03189 ** UTF-16 encoded strings and the other functions return UTF-8.
03190 **
03191 ** ^These APIs are only available if the library was compiled with the
03192 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
03193 **
03194 ** If two or more threads call one or more of these routines against the same
03195 ** prepared statement and column at the same time then the results are
03196 ** undefined.
03197 **
03198 ** If two or more threads call one or more
03199 ** [sqlite3_column_database_name | column metadata interfaces]
03200 ** for the same [prepared statement] and result column
03201 ** at the same time then the results are undefined.
03202 */
03203 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
03204 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
03205 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
03206 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
03207 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
03208 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
03209 
03210 /*
03211 ** CAPI3REF: Declared Datatype Of A Query Result
03212 **
03213 ** ^(The first parameter is a [prepared statement].
03214 ** If this statement is a [SELECT] statement and the Nth column of the
03215 ** returned result set of that [SELECT] is a table column (not an
03216 ** expression or subquery) then the declared type of the table
03217 ** column is returned.)^  ^If the Nth column of the result set is an
03218 ** expression or subquery, then a NULL pointer is returned.
03219 ** ^The returned string is always UTF-8 encoded.
03220 **
03221 ** ^(For example, given the database schema:
03222 **
03223 ** CREATE TABLE t1(c1 VARIANT);
03224 **
03225 ** and the following statement to be compiled:
03226 **
03227 ** SELECT c1 + 1, c1 FROM t1;
03228 **
03229 ** this routine would return the string "VARIANT" for the second result
03230 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
03231 **
03232 ** ^SQLite uses dynamic run-time typing.  ^So just because a column
03233 ** is declared to contain a particular type does not mean that the
03234 ** data stored in that column is of the declared type.  SQLite is
03235 ** strongly typed, but the typing is dynamic not static.  ^Type
03236 ** is associated with individual values, not with the containers
03237 ** used to hold those values.
03238 */
03239 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
03240 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
03241 
03242 /*
03243 ** CAPI3REF: Evaluate An SQL Statement
03244 **
03245 ** After a [prepared statement] has been prepared using either
03246 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
03247 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
03248 ** must be called one or more times to evaluate the statement.
03249 **
03250 ** The details of the behavior of the sqlite3_step() interface depend
03251 ** on whether the statement was prepared using the newer "v2" interface
03252 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
03253 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
03254 ** new "v2" interface is recommended for new applications but the legacy
03255 ** interface will continue to be supported.
03256 **
03257 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
03258 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
03259 ** ^With the "v2" interface, any of the other [result codes] or
03260 ** [extended result codes] might be returned as well.
03261 **
03262 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
03263 ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
03264 ** or occurs outside of an explicit transaction, then you can retry the
03265 ** statement.  If the statement is not a [COMMIT] and occurs within an
03266 ** explicit transaction then you should rollback the transaction before
03267 ** continuing.
03268 **
03269 ** ^[SQLITE_DONE] means that the statement has finished executing
03270 ** successfully.  sqlite3_step() should not be called again on this virtual
03271 ** machine without first calling [sqlite3_reset()] to reset the virtual
03272 ** machine back to its initial state.
03273 **
03274 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
03275 ** is returned each time a new row of data is ready for processing by the
03276 ** caller. The values may be accessed using the [column access functions].
03277 ** sqlite3_step() is called again to retrieve the next row of data.
03278 **
03279 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
03280 ** violation) has occurred.  sqlite3_step() should not be called again on
03281 ** the VM. More information may be found by calling [sqlite3_errmsg()].
03282 ** ^With the legacy interface, a more specific error code (for example,
03283 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
03284 ** can be obtained by calling [sqlite3_reset()] on the
03285 ** [prepared statement].  ^In the "v2" interface,
03286 ** the more specific error code is returned directly by sqlite3_step().
03287 **
03288 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
03289 ** Perhaps it was called on a [prepared statement] that has
03290 ** already been [sqlite3_finalize | finalized] or on one that had
03291 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
03292 ** be the case that the same database connection is being used by two or
03293 ** more threads at the same moment in time.
03294 **
03295 ** For all versions of SQLite up to and including 3.6.23.1, a call to
03296 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
03297 ** other than [SQLITE_ROW] before any subsequent invocation of
03298 ** sqlite3_step().  Failure to reset the prepared statement using 
03299 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
03300 ** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
03301 ** calling [sqlite3_reset()] automatically in this circumstance rather
03302 ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
03303 ** break because any application that ever receives an SQLITE_MISUSE error
03304 ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
03305 ** can be used to restore the legacy behavior.
03306 **
03307 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
03308 ** API always returns a generic error code, [SQLITE_ERROR], following any
03309 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
03310 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
03311 ** specific [error codes] that better describes the error.
03312 ** We admit that this is a goofy design.  The problem has been fixed
03313 ** with the "v2" interface.  If you prepare all of your SQL statements
03314 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
03315 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
03316 ** then the more specific [error codes] are returned directly
03317 ** by sqlite3_step().  The use of the "v2" interface is recommended.
03318 */
03319 SQLITE_API int sqlite3_step(sqlite3_stmt*);
03320 
03321 /*
03322 ** CAPI3REF: Number of columns in a result set
03323 **
03324 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
03325 ** current row of the result set of [prepared statement] P.
03326 ** ^If prepared statement P does not have results ready to return
03327 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
03328 ** interfaces) then sqlite3_data_count(P) returns 0.
03329 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
03330 **
03331 ** See also: [sqlite3_column_count()]
03332 */
03333 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
03334 
03335 /*
03336 ** CAPI3REF: Fundamental Datatypes
03337 ** KEYWORDS: SQLITE_TEXT
03338 **
03339 ** ^(Every value in SQLite has one of five fundamental datatypes:
03340 **
03341 ** <ul>
03342 ** <li> 64-bit signed integer
03343 ** <li> 64-bit IEEE floating point number
03344 ** <li> string
03345 ** <li> BLOB
03346 ** <li> NULL
03347 ** </ul>)^
03348 **
03349 ** These constants are codes for each of those types.
03350 **
03351 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
03352 ** for a completely different meaning.  Software that links against both
03353 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
03354 ** SQLITE_TEXT.
03355 */
03356 #define SQLITE_INTEGER  1
03357 #define SQLITE_FLOAT    2
03358 #define SQLITE_BLOB     4
03359 #define SQLITE_NULL     5
03360 #ifdef SQLITE_TEXT
03361 # undef SQLITE_TEXT
03362 #else
03363 # define SQLITE_TEXT     3
03364 #endif
03365 #define SQLITE3_TEXT     3
03366 
03367 /*
03368 ** CAPI3REF: Result Values From A Query
03369 ** KEYWORDS: {column access functions}
03370 **
03371 ** These routines form the "result set" interface.
03372 **
03373 ** ^These routines return information about a single column of the current
03374 ** result row of a query.  ^In every case the first argument is a pointer
03375 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
03376 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
03377 ** and the second argument is the index of the column for which information
03378 ** should be returned. ^The leftmost column of the result set has the index 0.
03379 ** ^The number of columns in the result can be determined using
03380 ** [sqlite3_column_count()].
03381 **
03382 ** If the SQL statement does not currently point to a valid row, or if the
03383 ** column index is out of range, the result is undefined.
03384 ** These routines may only be called when the most recent call to
03385 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
03386 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
03387 ** If any of these routines are called after [sqlite3_reset()] or
03388 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
03389 ** something other than [SQLITE_ROW], the results are undefined.
03390 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
03391 ** are called from a different thread while any of these routines
03392 ** are pending, then the results are undefined.
03393 **
03394 ** ^The sqlite3_column_type() routine returns the
03395 ** [SQLITE_INTEGER | datatype code] for the initial data type
03396 ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
03397 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
03398 ** returned by sqlite3_column_type() is only meaningful if no type
03399 ** conversions have occurred as described below.  After a type conversion,
03400 ** the value returned by sqlite3_column_type() is undefined.  Future
03401 ** versions of SQLite may change the behavior of sqlite3_column_type()
03402 ** following a type conversion.
03403 **
03404 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
03405 ** routine returns the number of bytes in that BLOB or string.
03406 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
03407 ** the string to UTF-8 and then returns the number of bytes.
03408 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
03409 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
03410 ** the number of bytes in that string.
03411 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
03412 **
03413 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
03414 ** routine returns the number of bytes in that BLOB or string.
03415 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
03416 ** the string to UTF-16 and then returns the number of bytes.
03417 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
03418 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
03419 ** the number of bytes in that string.
03420 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
03421 **
03422 ** ^The values returned by [sqlite3_column_bytes()] and 
03423 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
03424 ** of the string.  ^For clarity: the values returned by
03425 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
03426 ** bytes in the string, not the number of characters.
03427 **
03428 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
03429 ** even empty strings, are always zero terminated.  ^The return
03430 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
03431 **
03432 ** ^The object returned by [sqlite3_column_value()] is an
03433 ** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
03434 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
03435 ** If the [unprotected sqlite3_value] object returned by
03436 ** [sqlite3_column_value()] is used in any other way, including calls
03437 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
03438 ** or [sqlite3_value_bytes()], then the behavior is undefined.
03439 **
03440 ** These routines attempt to convert the value where appropriate.  ^For
03441 ** example, if the internal representation is FLOAT and a text result
03442 ** is requested, [sqlite3_snprintf()] is used internally to perform the
03443 ** conversion automatically.  ^(The following table details the conversions
03444 ** that are applied:
03445 **
03446 ** <blockquote>
03447 ** <table border="1">
03448 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
03449 **
03450 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
03451 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
03452 ** <tr><td>  NULL    <td>   TEXT    <td> Result is NULL pointer
03453 ** <tr><td>  NULL    <td>   BLOB    <td> Result is NULL pointer
03454 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
03455 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
03456 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
03457 ** <tr><td>  FLOAT   <td> INTEGER   <td> Convert from float to integer
03458 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
03459 ** <tr><td>  FLOAT   <td>   BLOB    <td> Same as FLOAT->TEXT
03460 ** <tr><td>  TEXT    <td> INTEGER   <td> Use atoi()
03461 ** <tr><td>  TEXT    <td>  FLOAT    <td> Use atof()
03462 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
03463 ** <tr><td>  BLOB    <td> INTEGER   <td> Convert to TEXT then use atoi()
03464 ** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
03465 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
03466 ** </table>
03467 ** </blockquote>)^
03468 **
03469 ** The table above makes reference to standard C library functions atoi()
03470 ** and atof().  SQLite does not really use these functions.  It has its
03471 ** own equivalent internal routines.  The atoi() and atof() names are
03472 ** used in the table for brevity and because they are familiar to most
03473 ** C programmers.
03474 **
03475 ** Note that when type conversions occur, pointers returned by prior
03476 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
03477 ** sqlite3_column_text16() may be invalidated.
03478 ** Type conversions and pointer invalidations might occur
03479 ** in the following cases:
03480 **
03481 ** <ul>
03482 ** <li> The initial content is a BLOB and sqlite3_column_text() or
03483 **      sqlite3_column_text16() is called.  A zero-terminator might
03484 **      need to be added to the string.</li>
03485 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
03486 **      sqlite3_column_text16() is called.  The content must be converted
03487 **      to UTF-16.</li>
03488 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
03489 **      sqlite3_column_text() is called.  The content must be converted
03490 **      to UTF-8.</li>
03491 ** </ul>
03492 **
03493 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
03494 ** not invalidate a prior pointer, though of course the content of the buffer
03495 ** that the prior pointer references will have been modified.  Other kinds
03496 ** of conversion are done in place when it is possible, but sometimes they
03497 ** are not possible and in those cases prior pointers are invalidated.
03498 **
03499 ** The safest and easiest to remember policy is to invoke these routines
03500 ** in one of the following ways:
03501 **
03502 ** <ul>
03503 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
03504 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
03505 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
03506 ** </ul>
03507 **
03508 ** In other words, you should call sqlite3_column_text(),
03509 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
03510 ** into the desired format, then invoke sqlite3_column_bytes() or
03511 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
03512 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
03513 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
03514 ** with calls to sqlite3_column_bytes().
03515 **
03516 ** ^The pointers returned are valid until a type conversion occurs as
03517 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
03518 ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
03519 ** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
03520 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
03521 ** [sqlite3_free()].
03522 **
03523 ** ^(If a memory allocation error occurs during the evaluation of any
03524 ** of these routines, a default value is returned.  The default value
03525 ** is either the integer 0, the floating point number 0.0, or a NULL
03526 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
03527 ** [SQLITE_NOMEM].)^
03528 */
03529 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
03530 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
03531 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
03532 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
03533 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
03534 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
03535 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
03536 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
03537 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
03538 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
03539 
03540 /*
03541 ** CAPI3REF: Destroy A Prepared Statement Object
03542 **
03543 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
03544 ** ^If the most recent evaluation of the statement encountered no errors
03545 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
03546 ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
03547 ** sqlite3_finalize(S) returns the appropriate [error code] or
03548 ** [extended error code].
03549 **
03550 ** ^The sqlite3_finalize(S) routine can be called at any point during
03551 ** the life cycle of [prepared statement] S:
03552 ** before statement S is ever evaluated, after
03553 ** one or more calls to [sqlite3_reset()], or after any call
03554 ** to [sqlite3_step()] regardless of whether or not the statement has
03555 ** completed execution.
03556 **
03557 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
03558 **
03559 ** The application must finalize every [prepared statement] in order to avoid
03560 ** resource leaks.  It is a grievous error for the application to try to use
03561 ** a prepared statement after it has been finalized.  Any use of a prepared
03562 ** statement after it has been finalized can result in undefined and
03563 ** undesirable behavior such as segfaults and heap corruption.
03564 */
03565 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
03566 
03567 /*
03568 ** CAPI3REF: Reset A Prepared Statement Object
03569 **
03570 ** The sqlite3_reset() function is called to reset a [prepared statement]
03571 ** object back to its initial state, ready to be re-executed.
03572 ** ^Any SQL statement variables that had values bound to them using
03573 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
03574 ** Use [sqlite3_clear_bindings()] to reset the bindings.
03575 **
03576 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
03577 ** back to the beginning of its program.
03578 **
03579 ** ^If the most recent call to [sqlite3_step(S)] for the
03580 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
03581 ** or if [sqlite3_step(S)] has never before been called on S,
03582 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
03583 **
03584 ** ^If the most recent call to [sqlite3_step(S)] for the
03585 ** [prepared statement] S indicated an error, then
03586 ** [sqlite3_reset(S)] returns an appropriate [error code].
03587 **
03588 ** ^The [sqlite3_reset(S)] interface does not change the values
03589 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
03590 */
03591 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
03592 
03593 /*
03594 ** CAPI3REF: Create Or Redefine SQL Functions
03595 ** KEYWORDS: {function creation routines}
03596 ** KEYWORDS: {application-defined SQL function}
03597 ** KEYWORDS: {application-defined SQL functions}
03598 **
03599 ** ^These functions (collectively known as "function creation routines")
03600 ** are used to add SQL functions or aggregates or to redefine the behavior
03601 ** of existing SQL functions or aggregates.  The only differences between
03602 ** these routines are the text encoding expected for
03603 ** the second parameter (the name of the function being created)
03604 ** and the presence or absence of a destructor callback for
03605 ** the application data pointer.
03606 **
03607 ** ^The first parameter is the [database connection] to which the SQL
03608 ** function is to be added.  ^If an application uses more than one database
03609 ** connection then application-defined SQL functions must be added
03610 ** to each database connection separately.
03611 **
03612 ** ^The second parameter is the name of the SQL function to be created or
03613 ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
03614 ** representation, exclusive of the zero-terminator.  ^Note that the name
03615 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.  
03616 ** ^Any attempt to create a function with a longer name
03617 ** will result in [SQLITE_MISUSE] being returned.
03618 **
03619 ** ^The third parameter (nArg)
03620 ** is the number of arguments that the SQL function or
03621 ** aggregate takes. ^If this parameter is -1, then the SQL function or
03622 ** aggregate may take any number of arguments between 0 and the limit
03623 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
03624 ** parameter is less than -1 or greater than 127 then the behavior is
03625 ** undefined.
03626 **
03627 ** ^The fourth parameter, eTextRep, specifies what
03628 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
03629 ** its parameters.  Every SQL function implementation must be able to work
03630 ** with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
03631 ** more efficient with one encoding than another.  ^An application may
03632 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
03633 ** times with the same function but with different values of eTextRep.
03634 ** ^When multiple implementations of the same function are available, SQLite
03635 ** will pick the one that involves the least amount of data conversion.
03636 ** If there is only a single implementation which does not care what text
03637 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
03638 **
03639 ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
03640 ** function can gain access to this pointer using [sqlite3_user_data()].)^
03641 **
03642 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
03643 ** pointers to C-language functions that implement the SQL function or
03644 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
03645 ** callback only; NULL pointers must be passed as the xStep and xFinal
03646 ** parameters. ^An aggregate SQL function requires an implementation of xStep
03647 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
03648 ** SQL function or aggregate, pass NULL pointers for all three function
03649 ** callbacks.
03650 **
03651 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
03652 ** then it is destructor for the application data pointer. 
03653 ** The destructor is invoked when the function is deleted, either by being
03654 ** overloaded or when the database connection closes.)^
03655 ** ^The destructor is also invoked if the call to
03656 ** sqlite3_create_function_v2() fails.
03657 ** ^When the destructor callback of the tenth parameter is invoked, it
03658 ** is passed a single argument which is a copy of the application data 
03659 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
03660 **
03661 ** ^It is permitted to register multiple implementations of the same
03662 ** functions with the same name but with either differing numbers of
03663 ** arguments or differing preferred text encodings.  ^SQLite will use
03664 ** the implementation that most closely matches the way in which the
03665 ** SQL function is used.  ^A function implementation with a non-negative
03666 ** nArg parameter is a better match than a function implementation with
03667 ** a negative nArg.  ^A function where the preferred text encoding
03668 ** matches the database encoding is a better
03669 ** match than a function where the encoding is different.  
03670 ** ^A function where the encoding difference is between UTF16le and UTF16be
03671 ** is a closer match than a function where the encoding difference is
03672 ** between UTF8 and UTF16.
03673 **
03674 ** ^Built-in functions may be overloaded by new application-defined functions.
03675 **
03676 ** ^An application-defined function is permitted to call other
03677 ** SQLite interfaces.  However, such calls must not
03678 ** close the database connection nor finalize or reset the prepared
03679 ** statement in which the function is running.
03680 */
03681 SQLITE_API int sqlite3_create_function(
03682   sqlite3 *db,
03683   const char *zFunctionName,
03684   int nArg,
03685   int eTextRep,
03686   void *pApp,
03687   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
03688   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
03689   void (*xFinal)(sqlite3_context*)
03690 );
03691 SQLITE_API int sqlite3_create_function16(
03692   sqlite3 *db,
03693   const void *zFunctionName,
03694   int nArg,
03695   int eTextRep,
03696   void *pApp,
03697   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
03698   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
03699   void (*xFinal)(sqlite3_context*)
03700 );
03701 SQLITE_API int sqlite3_create_function_v2(
03702   sqlite3 *db,
03703   const char *zFunctionName,
03704   int nArg,
03705   int eTextRep,
03706   void *pApp,
03707   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
03708   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
03709   void (*xFinal)(sqlite3_context*),
03710   void(*xDestroy)(void*)
03711 );
03712 
03713 /*
03714 ** CAPI3REF: Text Encodings
03715 **
03716 ** These constant define integer codes that represent the various
03717 ** text encodings supported by SQLite.
03718 */
03719 #define SQLITE_UTF8           1
03720 #define SQLITE_UTF16LE        2
03721 #define SQLITE_UTF16BE        3
03722 #define SQLITE_UTF16          4    /* Use native byte order */
03723 #define SQLITE_ANY            5    /* sqlite3_create_function only */
03724 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
03725 
03726 /*
03727 ** CAPI3REF: Deprecated Functions
03728 ** DEPRECATED
03729 **
03730 ** These functions are [deprecated].  In order to maintain
03731 ** backwards compatibility with older code, these functions continue 
03732 ** to be supported.  However, new applications should avoid
03733 ** the use of these functions.  To help encourage people to avoid
03734 ** using these functions, we are not going to tell you what they do.
03735 */
03736 #ifndef SQLITE_OMIT_DEPRECATED
03737 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
03738 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
03739 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
03740 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
03741 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
03742 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
03743 #endif
03744 
03745 /*
03746 ** CAPI3REF: Obtaining SQL Function Parameter Values
03747 **
03748 ** The C-language implementation of SQL functions and aggregates uses
03749 ** this set of interface routines to access the parameter values on
03750 ** the function or aggregate.
03751 **
03752 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
03753 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
03754 ** define callbacks that implement the SQL functions and aggregates.
03755 ** The 3rd parameter to these callbacks is an array of pointers to
03756 ** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
03757 ** each parameter to the SQL function.  These routines are used to
03758 ** extract values from the [sqlite3_value] objects.
03759 **
03760 ** These routines work only with [protected sqlite3_value] objects.
03761 ** Any attempt to use these routines on an [unprotected sqlite3_value]
03762 ** object results in undefined behavior.
03763 **
03764 ** ^These routines work just like the corresponding [column access functions]
03765 ** except that  these routines take a single [protected sqlite3_value] object
03766 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
03767 **
03768 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
03769 ** in the native byte-order of the host machine.  ^The
03770 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
03771 ** extract UTF-16 strings as big-endian and little-endian respectively.
03772 **
03773 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
03774 ** numeric affinity to the value.  This means that an attempt is
03775 ** made to convert the value to an integer or floating point.  If
03776 ** such a conversion is possible without loss of information (in other
03777 ** words, if the value is a string that looks like a number)
03778 ** then the conversion is performed.  Otherwise no conversion occurs.
03779 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
03780 **
03781 ** Please pay particular attention to the fact that the pointer returned
03782 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
03783 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
03784 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
03785 ** or [sqlite3_value_text16()].
03786 **
03787 ** These routines must be called from the same thread as
03788 ** the SQL function that supplied the [sqlite3_value*] parameters.
03789 */
03790 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
03791 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
03792 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
03793 SQLITE_API double sqlite3_value_double(sqlite3_value*);
03794 SQLITE_API int sqlite3_value_int(sqlite3_value*);
03795 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
03796 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
03797 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
03798 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
03799 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
03800 SQLITE_API int sqlite3_value_type(sqlite3_value*);
03801 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
03802 
03803 /*
03804 ** CAPI3REF: Obtain Aggregate Function Context
03805 **
03806 ** Implementations of aggregate SQL functions use this
03807 ** routine to allocate memory for storing their state.
03808 **
03809 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 
03810 ** for a particular aggregate function, SQLite
03811 ** allocates N of memory, zeroes out that memory, and returns a pointer
03812 ** to the new memory. ^On second and subsequent calls to
03813 ** sqlite3_aggregate_context() for the same aggregate function instance,
03814 ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
03815 ** called once for each invocation of the xStep callback and then one
03816 ** last time when the xFinal callback is invoked.  ^(When no rows match
03817 ** an aggregate query, the xStep() callback of the aggregate function
03818 ** implementation is never called and xFinal() is called exactly once.
03819 ** In those cases, sqlite3_aggregate_context() might be called for the
03820 ** first time from within xFinal().)^
03821 **
03822 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
03823 ** less than or equal to zero or if a memory allocate error occurs.
03824 **
03825 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
03826 ** determined by the N parameter on first successful call.  Changing the
03827 ** value of N in subsequent call to sqlite3_aggregate_context() within
03828 ** the same aggregate function instance will not resize the memory
03829 ** allocation.)^
03830 **
03831 ** ^SQLite automatically frees the memory allocated by 
03832 ** sqlite3_aggregate_context() when the aggregate query concludes.
03833 **
03834 ** The first parameter must be a copy of the
03835 ** [sqlite3_context | SQL function context] that is the first parameter
03836 ** to the xStep or xFinal callback routine that implements the aggregate
03837 ** function.
03838 **
03839 ** This routine must be called from the same thread in which
03840 ** the aggregate SQL function is running.
03841 */
03842 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
03843 
03844 /*
03845 ** CAPI3REF: User Data For Functions
03846 **
03847 ** ^The sqlite3_user_data() interface returns a copy of
03848 ** the pointer that was the pUserData parameter (the 5th parameter)
03849 ** of the [sqlite3_create_function()]
03850 ** and [sqlite3_create_function16()] routines that originally
03851 ** registered the application defined function.
03852 **
03853 ** This routine must be called from the same thread in which
03854 ** the application-defined function is running.
03855 */
03856 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
03857 
03858 /*
03859 ** CAPI3REF: Database Connection For Functions
03860 **
03861 ** ^The sqlite3_context_db_handle() interface returns a copy of
03862 ** the pointer to the [database connection] (the 1st parameter)
03863 ** of the [sqlite3_create_function()]
03864 ** and [sqlite3_create_function16()] routines that originally
03865 ** registered the application defined function.
03866 */
03867 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
03868 
03869 /*
03870 ** CAPI3REF: Function Auxiliary Data
03871 **
03872 ** The following two functions may be used by scalar SQL functions to
03873 ** associate metadata with argument values. If the same value is passed to
03874 ** multiple invocations of the same SQL function during query execution, under
03875 ** some circumstances the associated metadata may be preserved. This may
03876 ** be used, for example, to add a regular-expression matching scalar
03877 ** function. The compiled version of the regular expression is stored as
03878 ** metadata associated with the SQL value passed as the regular expression
03879 ** pattern.  The compiled regular expression can be reused on multiple
03880 ** invocations of the same function so that the original pattern string
03881 ** does not need to be recompiled on each invocation.
03882 **
03883 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
03884 ** associated by the sqlite3_set_auxdata() function with the Nth argument
03885 ** value to the application-defined function. ^If no metadata has been ever
03886 ** been set for the Nth argument of the function, or if the corresponding
03887 ** function parameter has changed since the meta-data was set,
03888 ** then sqlite3_get_auxdata() returns a NULL pointer.
03889 **
03890 ** ^The sqlite3_set_auxdata() interface saves the metadata
03891 ** pointed to by its 3rd parameter as the metadata for the N-th
03892 ** argument of the application-defined function.  Subsequent
03893 ** calls to sqlite3_get_auxdata() might return this data, if it has
03894 ** not been destroyed.
03895 ** ^If it is not NULL, SQLite will invoke the destructor
03896 ** function given by the 4th parameter to sqlite3_set_auxdata() on
03897 ** the metadata when the corresponding function parameter changes
03898 ** or when the SQL statement completes, whichever comes first.
03899 **
03900 ** SQLite is free to call the destructor and drop metadata on any
03901 ** parameter of any function at any time.  ^The only guarantee is that
03902 ** the destructor will be called before the metadata is dropped.
03903 **
03904 ** ^(In practice, metadata is preserved between function calls for
03905 ** expressions that are constant at compile time. This includes literal
03906 ** values and [parameters].)^
03907 **
03908 ** These routines must be called from the same thread in which
03909 ** the SQL function is running.
03910 */
03911 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
03912 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
03913 
03914 
03915 /*
03916 ** CAPI3REF: Constants Defining Special Destructor Behavior
03917 **
03918 ** These are special values for the destructor that is passed in as the
03919 ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
03920 ** argument is SQLITE_STATIC, it means that the content pointer is constant
03921 ** and will never change.  It does not need to be destroyed.  ^The
03922 ** SQLITE_TRANSIENT value means that the content will likely change in
03923 ** the near future and that SQLite should make its own private copy of
03924 ** the content before returning.
03925 **
03926 ** The typedef is necessary to work around problems in certain
03927 ** C++ compilers.  See ticket #2191.
03928 */
03929 typedef void (*sqlite3_destructor_type)(void*);
03930 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
03931 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
03932 
03933 /*
03934 ** CAPI3REF: Setting The Result Of An SQL Function
03935 **
03936 ** These routines are used by the xFunc or xFinal callbacks that
03937 ** implement SQL functions and aggregates.  See
03938 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
03939 ** for additional information.
03940 **
03941 ** These functions work very much like the [parameter binding] family of
03942 ** functions used to bind values to host parameters in prepared statements.
03943 ** Refer to the [SQL parameter] documentation for additional information.
03944 **
03945 ** ^The sqlite3_result_blob() interface sets the result from
03946 ** an application-defined function to be the BLOB whose content is pointed
03947 ** to by the second parameter and which is N bytes long where N is the
03948 ** third parameter.
03949 **
03950 ** ^The sqlite3_result_zeroblob() interfaces set the result of
03951 ** the application-defined function to be a BLOB containing all zero
03952 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
03953 **
03954 ** ^The sqlite3_result_double() interface sets the result from
03955 ** an application-defined function to be a floating point value specified
03956 ** by its 2nd argument.
03957 **
03958 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
03959 ** cause the implemented SQL function to throw an exception.
03960 ** ^SQLite uses the string pointed to by the
03961 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
03962 ** as the text of an error message.  ^SQLite interprets the error
03963 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
03964 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
03965 ** byte order.  ^If the third parameter to sqlite3_result_error()
03966 ** or sqlite3_result_error16() is negative then SQLite takes as the error
03967 ** message all text up through the first zero character.
03968 ** ^If the third parameter to sqlite3_result_error() or
03969 ** sqlite3_result_error16() is non-negative then SQLite takes that many
03970 ** bytes (not characters) from the 2nd parameter as the error message.
03971 ** ^The sqlite3_result_error() and sqlite3_result_error16()
03972 ** routines make a private copy of the error message text before
03973 ** they return.  Hence, the calling function can deallocate or
03974 ** modify the text after they return without harm.
03975 ** ^The sqlite3_result_error_code() function changes the error code
03976 ** returned by SQLite as a result of an error in a function.  ^By default,
03977 ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
03978 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
03979 **
03980 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
03981 ** indicating that a string or BLOB is too long to represent.
03982 **
03983 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
03984 ** indicating that a memory allocation failed.
03985 **
03986 ** ^The sqlite3_result_int() interface sets the return value
03987 ** of the application-defined function to be the 32-bit signed integer
03988 ** value given in the 2nd argument.
03989 ** ^The sqlite3_result_int64() interface sets the return value
03990 ** of the application-defined function to be the 64-bit signed integer
03991 ** value given in the 2nd argument.
03992 **
03993 ** ^The sqlite3_result_null() interface sets the return value
03994 ** of the application-defined function to be NULL.
03995 **
03996 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
03997 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
03998 ** set the return value of the application-defined function to be
03999 ** a text string which is represented as UTF-8, UTF-16 native byte order,
04000 ** UTF-16 little endian, or UTF-16 big endian, respectively.
04001 ** ^SQLite takes the text result from the application from
04002 ** the 2nd parameter of the sqlite3_result_text* interfaces.
04003 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
04004 ** is negative, then SQLite takes result text from the 2nd parameter
04005 ** through the first zero character.
04006 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
04007 ** is non-negative, then as many bytes (not characters) of the text
04008 ** pointed to by the 2nd parameter are taken as the application-defined
04009 ** function result.
04010 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
04011 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
04012 ** function as the destructor on the text or BLOB result when it has
04013 ** finished using that result.
04014 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
04015 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
04016 ** assumes that the text or BLOB result is in constant space and does not
04017 ** copy the content of the parameter nor call a destructor on the content
04018 ** when it has finished using that result.
04019 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
04020 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
04021 ** then SQLite makes a copy of the result into space obtained from
04022 ** from [sqlite3_malloc()] before it returns.
04023 **
04024 ** ^The sqlite3_result_value() interface sets the result of
04025 ** the application-defined function to be a copy the
04026 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
04027 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
04028 ** so that the [sqlite3_value] specified in the parameter may change or
04029 ** be deallocated after sqlite3_result_value() returns without harm.
04030 ** ^A [protected sqlite3_value] object may always be used where an
04031 ** [unprotected sqlite3_value] object is required, so either
04032 ** kind of [sqlite3_value] object can be used with this interface.
04033 **
04034 ** If these routines are called from within the different thread
04035 ** than the one containing the application-defined function that received
04036 ** the [sqlite3_context] pointer, the results are undefined.
04037 */
04038 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
04039 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
04040 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
04041 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
04042 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
04043 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
04044 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
04045 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
04046 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
04047 SQLITE_API void sqlite3_result_null(sqlite3_context*);
04048 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
04049 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
04050 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
04051 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
04052 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
04053 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
04054 
04055 /*
04056 ** CAPI3REF: Define New Collating Sequences
04057 **
04058 ** ^These functions add, remove, or modify a [collation] associated
04059 ** with the [database connection] specified as the first argument.
04060 **
04061 ** ^The name of the collation is a UTF-8 string
04062 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
04063 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
04064 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
04065 ** considered to be the same name.
04066 **
04067 ** ^(The third argument (eTextRep) must be one of the constants:
04068 ** <ul>
04069 ** <li> [SQLITE_UTF8],
04070 ** <li> [SQLITE_UTF16LE],
04071 ** <li> [SQLITE_UTF16BE],
04072 ** <li> [SQLITE_UTF16], or
04073 ** <li> [SQLITE_UTF16_ALIGNED].
04074 ** </ul>)^
04075 ** ^The eTextRep argument determines the encoding of strings passed
04076 ** to the collating function callback, xCallback.
04077 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
04078 ** force strings to be UTF16 with native byte order.
04079 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
04080 ** on an even byte address.
04081 **
04082 ** ^The fourth argument, pArg, is an application data pointer that is passed
04083 ** through as the first argument to the collating function callback.
04084 **
04085 ** ^The fifth argument, xCallback, is a pointer to the collating function.
04086 ** ^Multiple collating functions can be registered using the same name but
04087 ** with different eTextRep parameters and SQLite will use whichever
04088 ** function requires the least amount of data transformation.
04089 ** ^If the xCallback argument is NULL then the collating function is
04090 ** deleted.  ^When all collating functions having the same name are deleted,
04091 ** that collation is no longer usable.
04092 **
04093 ** ^The collating function callback is invoked with a copy of the pArg 
04094 ** application data pointer and with two strings in the encoding specified
04095 ** by the eTextRep argument.  The collating function must return an
04096 ** integer that is negative, zero, or positive
04097 ** if the first string is less than, equal to, or greater than the second,
04098 ** respectively.  A collating function must always return the same answer
04099 ** given the same inputs.  If two or more collating functions are registered
04100 ** to the same collation name (using different eTextRep values) then all
04101 ** must give an equivalent answer when invoked with equivalent strings.
04102 ** The collating function must obey the following properties for all
04103 ** strings A, B, and C:
04104 **
04105 ** <ol>
04106 ** <li> If A==B then B==A.
04107 ** <li> If A==B and B==C then A==C.
04108 ** <li> If A&lt;B THEN B&gt;A.
04109 ** <li> If A&lt;B and B&lt;C then A&lt;C.
04110 ** </ol>
04111 **
04112 ** If a collating function fails any of the above constraints and that
04113 ** collating function is  registered and used, then the behavior of SQLite
04114 ** is undefined.
04115 **
04116 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
04117 ** with the addition that the xDestroy callback is invoked on pArg when
04118 ** the collating function is deleted.
04119 ** ^Collating functions are deleted when they are overridden by later
04120 ** calls to the collation creation functions or when the
04121 ** [database connection] is closed using [sqlite3_close()].
04122 **
04123 ** ^The xDestroy callback is <u>not</u> called if the 
04124 ** sqlite3_create_collation_v2() function fails.  Applications that invoke
04125 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 
04126 ** check the return code and dispose of the application data pointer
04127 ** themselves rather than expecting SQLite to deal with it for them.
04128 ** This is different from every other SQLite interface.  The inconsistency 
04129 ** is unfortunate but cannot be changed without breaking backwards 
04130 ** compatibility.
04131 **
04132 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
04133 */
04134 SQLITE_API int sqlite3_create_collation(
04135   sqlite3*, 
04136   const char *zName, 
04137   int eTextRep, 
04138   void *pArg,
04139   int(*xCompare)(void*,int,const void*,int,const void*)
04140 );
04141 SQLITE_API int sqlite3_create_collation_v2(
04142   sqlite3*, 
04143   const char *zName, 
04144   int eTextRep, 
04145   void *pArg,
04146   int(*xCompare)(void*,int,const void*,int,const void*),
04147   void(*xDestroy)(void*)
04148 );
04149 SQLITE_API int sqlite3_create_collation16(
04150   sqlite3*, 
04151   const void *zName,
04152   int eTextRep, 
04153   void *pArg,
04154   int(*xCompare)(void*,int,const void*,int,const void*)
04155 );
04156 
04157 /*
04158 ** CAPI3REF: Collation Needed Callbacks
04159 **
04160 ** ^To avoid having to register all collation sequences before a database
04161 ** can be used, a single callback function may be registered with the
04162 ** [database connection] to be invoked whenever an undefined collation
04163 ** sequence is required.
04164 **
04165 ** ^If the function is registered using the sqlite3_collation_needed() API,
04166 ** then it is passed the names of undefined collation sequences as strings
04167 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
04168 ** the names are passed as UTF-16 in machine native byte order.
04169 ** ^A call to either function replaces the existing collation-needed callback.
04170 **
04171 ** ^(When the callback is invoked, the first argument passed is a copy
04172 ** of the second argument to sqlite3_collation_needed() or
04173 ** sqlite3_collation_needed16().  The second argument is the database
04174 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
04175 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
04176 ** sequence function required.  The fourth parameter is the name of the
04177 ** required collation sequence.)^
04178 **
04179 ** The callback function should register the desired collation using
04180 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
04181 ** [sqlite3_create_collation_v2()].
04182 */
04183 SQLITE_API int sqlite3_collation_needed(
04184   sqlite3*, 
04185   void*, 
04186   void(*)(void*,sqlite3*,int eTextRep,const char*)
04187 );
04188 SQLITE_API int sqlite3_collation_needed16(
04189   sqlite3*, 
04190   void*,
04191   void(*)(void*,sqlite3*,int eTextRep,const void*)
04192 );
04193 
04194 #ifdef SQLITE_HAS_CODEC
04195 /*
04196 ** Specify the key for an encrypted database.  This routine should be
04197 ** called right after sqlite3_open().
04198 **
04199 ** The code to implement this API is not available in the public release
04200 ** of SQLite.
04201 */
04202 SQLITE_API int sqlite3_key(
04203   sqlite3 *db,                   /* Database to be rekeyed */
04204   const void *pKey, int nKey     /* The key */
04205 );
04206 
04207 /*
04208 ** Change the key on an open database.  If the current database is not
04209 ** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
04210 ** database is decrypted.
04211 **
04212 ** The code to implement this API is not available in the public release
04213 ** of SQLite.
04214 */
04215 SQLITE_API int sqlite3_rekey(
04216   sqlite3 *db,                   /* Database to be rekeyed */
04217   const void *pKey, int nKey     /* The new key */
04218 );
04219 
04220 /*
04221 ** Specify the activation key for a SEE database.  Unless 
04222 ** activated, none of the SEE routines will work.
04223 */
04224 SQLITE_API void sqlite3_activate_see(
04225   const char *zPassPhrase        /* Activation phrase */
04226 );
04227 #endif
04228 
04229 #ifdef SQLITE_ENABLE_CEROD
04230 /*
04231 ** Specify the activation key for a CEROD database.  Unless 
04232 ** activated, none of the CEROD routines will work.
04233 */
04234 SQLITE_API void sqlite3_activate_cerod(
04235   const char *zPassPhrase        /* Activation phrase */
04236 );
04237 #endif
04238 
04239 /*
04240 ** CAPI3REF: Suspend Execution For A Short Time
04241 **
04242 ** The sqlite3_sleep() function causes the current thread to suspend execution
04243 ** for at least a number of milliseconds specified in its parameter.
04244 **
04245 ** If the operating system does not support sleep requests with
04246 ** millisecond time resolution, then the time will be rounded up to
04247 ** the nearest second. The number of milliseconds of sleep actually
04248 ** requested from the operating system is returned.
04249 **
04250 ** ^SQLite implements this interface by calling the xSleep()
04251 ** method of the default [sqlite3_vfs] object.  If the xSleep() method
04252 ** of the default VFS is not implemented correctly, or not implemented at
04253 ** all, then the behavior of sqlite3_sleep() may deviate from the description
04254 ** in the previous paragraphs.
04255 */
04256 SQLITE_API int sqlite3_sleep(int);
04257 
04258 /*
04259 ** CAPI3REF: Name Of The Folder Holding Temporary Files
04260 **
04261 ** ^(If this global variable is made to point to a string which is
04262 ** the name of a folder (a.k.a. directory), then all temporary files
04263 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
04264 ** will be placed in that directory.)^  ^If this variable
04265 ** is a NULL pointer, then SQLite performs a search for an appropriate
04266 ** temporary file directory.
04267 **
04268 ** It is not safe to read or modify this variable in more than one
04269 ** thread at a time.  It is not safe to read or modify this variable
04270 ** if a [database connection] is being used at the same time in a separate
04271 ** thread.
04272 ** It is intended that this variable be set once
04273 ** as part of process initialization and before any SQLite interface
04274 ** routines have been called and that this variable remain unchanged
04275 ** thereafter.
04276 **
04277 ** ^The [temp_store_directory pragma] may modify this variable and cause
04278 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
04279 ** the [temp_store_directory pragma] always assumes that any string
04280 ** that this variable points to is held in memory obtained from 
04281 ** [sqlite3_malloc] and the pragma may attempt to free that memory
04282 ** using [sqlite3_free].
04283 ** Hence, if this variable is modified directly, either it should be
04284 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
04285 ** or else the use of the [temp_store_directory pragma] should be avoided.
04286 */
04287 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
04288 
04289 /*
04290 ** CAPI3REF: Test For Auto-Commit Mode
04291 ** KEYWORDS: {autocommit mode}
04292 **
04293 ** ^The sqlite3_get_autocommit() interface returns non-zero or
04294 ** zero if the given database connection is or is not in autocommit mode,
04295 ** respectively.  ^Autocommit mode is on by default.
04296 ** ^Autocommit mode is disabled by a [BEGIN] statement.
04297 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
04298 **
04299 ** If certain kinds of errors occur on a statement within a multi-statement
04300 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
04301 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
04302 ** transaction might be rolled back automatically.  The only way to
04303 ** find out whether SQLite automatically rolled back the transaction after
04304 ** an error is to use this function.
04305 **
04306 ** If another thread changes the autocommit status of the database
04307 ** connection while this routine is running, then the return value
04308 ** is undefined.
04309 */
04310 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
04311 
04312 /*
04313 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
04314 **
04315 ** ^The sqlite3_db_handle interface returns the [database connection] handle
04316 ** to which a [prepared statement] belongs.  ^The [database connection]
04317 ** returned by sqlite3_db_handle is the same [database connection]
04318 ** that was the first argument
04319 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
04320 ** create the statement in the first place.
04321 */
04322 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
04323 
04324 /*
04325 ** CAPI3REF: Find the next prepared statement
04326 **
04327 ** ^This interface returns a pointer to the next [prepared statement] after
04328 ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
04329 ** then this interface returns a pointer to the first prepared statement
04330 ** associated with the database connection pDb.  ^If no prepared statement
04331 ** satisfies the conditions of this routine, it returns NULL.
04332 **
04333 ** The [database connection] pointer D in a call to
04334 ** [sqlite3_next_stmt(D,S)] must refer to an open database
04335 ** connection and in particular must not be a NULL pointer.
04336 */
04337 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
04338 
04339 /*
04340 ** CAPI3REF: Commit And Rollback Notification Callbacks
04341 **
04342 ** ^The sqlite3_commit_hook() interface registers a callback
04343 ** function to be invoked whenever a transaction is [COMMIT | committed].
04344 ** ^Any callback set by a previous call to sqlite3_commit_hook()
04345 ** for the same database connection is overridden.
04346 ** ^The sqlite3_rollback_hook() interface registers a callback
04347 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
04348 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
04349 ** for the same database connection is overridden.
04350 ** ^The pArg argument is passed through to the callback.
04351 ** ^If the callback on a commit hook function returns non-zero,
04352 ** then the commit is converted into a rollback.
04353 **
04354 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
04355 ** return the P argument from the previous call of the same function
04356 ** on the same [database connection] D, or NULL for
04357 ** the first call for each function on D.
04358 **
04359 ** The callback implementation must not do anything that will modify
04360 ** the database connection that invoked the callback.  Any actions
04361 ** to modify the database connection must be deferred until after the
04362 ** completion of the [sqlite3_step()] call that triggered the commit
04363 ** or rollback hook in the first place.
04364 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
04365 ** database connections for the meaning of "modify" in this paragraph.
04366 **
04367 ** ^Registering a NULL function disables the callback.
04368 **
04369 ** ^When the commit hook callback routine returns zero, the [COMMIT]
04370 ** operation is allowed to continue normally.  ^If the commit hook
04371 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
04372 ** ^The rollback hook is invoked on a rollback that results from a commit
04373 ** hook returning non-zero, just as it would be with any other rollback.
04374 **
04375 ** ^For the purposes of this API, a transaction is said to have been
04376 ** rolled back if an explicit "ROLLBACK" statement is executed, or
04377 ** an error or constraint causes an implicit rollback to occur.
04378 ** ^The rollback callback is not invoked if a transaction is
04379 ** automatically rolled back because the database connection is closed.
04380 **
04381 ** See also the [sqlite3_update_hook()] interface.
04382 */
04383 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
04384 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
04385 
04386 /*
04387 ** CAPI3REF: Data Change Notification Callbacks
04388 **
04389 ** ^The sqlite3_update_hook() interface registers a callback function
04390 ** with the [database connection] identified by the first argument
04391 ** to be invoked whenever a row is updated, inserted or deleted.
04392 ** ^Any callback set by a previous call to this function
04393 ** for the same database connection is overridden.
04394 **
04395 ** ^The second argument is a pointer to the function to invoke when a
04396 ** row is updated, inserted or deleted.
04397 ** ^The first argument to the callback is a copy of the third argument
04398 ** to sqlite3_update_hook().
04399 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
04400 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
04401 ** to be invoked.
04402 ** ^The third and fourth arguments to the callback contain pointers to the
04403 ** database and table name containing the affected row.
04404 ** ^The final callback parameter is the [rowid] of the row.
04405 ** ^In the case of an update, this is the [rowid] after the update takes place.
04406 **
04407 ** ^(The update hook is not invoked when internal system tables are
04408 ** modified (i.e. sqlite_master and sqlite_sequence).)^
04409 **
04410 ** ^In the current implementation, the update hook
04411 ** is not invoked when duplication rows are deleted because of an
04412 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
04413 ** invoked when rows are deleted using the [truncate optimization].
04414 ** The exceptions defined in this paragraph might change in a future
04415 ** release of SQLite.
04416 **
04417 ** The update hook implementation must not do anything that will modify
04418 ** the database connection that invoked the update hook.  Any actions
04419 ** to modify the database connection must be deferred until after the
04420 ** completion of the [sqlite3_step()] call that triggered the update hook.
04421 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
04422 ** database connections for the meaning of "modify" in this paragraph.
04423 **
04424 ** ^The sqlite3_update_hook(D,C,P) function
04425 ** returns the P argument from the previous call
04426 ** on the same [database connection] D, or NULL for
04427 ** the first call on D.
04428 **
04429 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
04430 ** interfaces.
04431 */
04432 SQLITE_API void *sqlite3_update_hook(
04433   sqlite3*, 
04434   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
04435   void*
04436 );
04437 
04438 /*
04439 ** CAPI3REF: Enable Or Disable Shared Pager Cache
04440 ** KEYWORDS: {shared cache}
04441 **
04442 ** ^(This routine enables or disables the sharing of the database cache
04443 ** and schema data structures between [database connection | connections]
04444 ** to the same database. Sharing is enabled if the argument is true
04445 ** and disabled if the argument is false.)^
04446 **
04447 ** ^Cache sharing is enabled and disabled for an entire process.
04448 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
04449 ** sharing was enabled or disabled for each thread separately.
04450 **
04451 ** ^(The cache sharing mode set by this interface effects all subsequent
04452 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
04453 ** Existing database connections continue use the sharing mode
04454 ** that was in effect at the time they were opened.)^
04455 **
04456 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
04457 ** successfully.  An [error code] is returned otherwise.)^
04458 **
04459 ** ^Shared cache is disabled by default. But this might change in
04460 ** future releases of SQLite.  Applications that care about shared
04461 ** cache setting should set it explicitly.
04462 **
04463 ** See Also:  [SQLite Shared-Cache Mode]
04464 */
04465 SQLITE_API int sqlite3_enable_shared_cache(int);
04466 
04467 /*
04468 ** CAPI3REF: Attempt To Free Heap Memory
04469 **
04470 ** ^The sqlite3_release_memory() interface attempts to free N bytes
04471 ** of heap memory by deallocating non-essential memory allocations
04472 ** held by the database library.   Memory used to cache database
04473 ** pages to improve performance is an example of non-essential memory.
04474 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
04475 ** which might be more or less than the amount requested.
04476 ** ^The sqlite3_release_memory() routine is a no-op returning zero
04477 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
04478 */
04479 SQLITE_API int sqlite3_release_memory(int);
04480 
04481 /*
04482 ** CAPI3REF: Impose A Limit On Heap Size
04483 **
04484 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
04485 ** soft limit on the amount of heap memory that may be allocated by SQLite.
04486 ** ^SQLite strives to keep heap memory utilization below the soft heap
04487 ** limit by reducing the number of pages held in the page cache
04488 ** as heap memory usages approaches the limit.
04489 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
04490 ** below the limit, it will exceed the limit rather than generate
04491 ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
04492 ** is advisory only.
04493 **
04494 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
04495 ** the soft heap limit prior to the call.  ^If the argument N is negative
04496 ** then no change is made to the soft heap limit.  Hence, the current
04497 ** size of the soft heap limit can be determined by invoking
04498 ** sqlite3_soft_heap_limit64() with a negative argument.
04499 **
04500 ** ^If the argument N is zero then the soft heap limit is disabled.
04501 **
04502 ** ^(The soft heap limit is not enforced in the current implementation
04503 ** if one or more of following conditions are true:
04504 **
04505 ** <ul>
04506 ** <li> The soft heap limit is set to zero.
04507 ** <li> Memory accounting is disabled using a combination of the
04508 **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
04509 **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
04510 ** <li> An alternative page cache implementation is specified using
04511 **      [sqlite3_config]([SQLITE_CONFIG_PCACHE],...).
04512 ** <li> The page cache allocates from its own memory pool supplied
04513 **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
04514 **      from the heap.
04515 ** </ul>)^
04516 **
04517 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
04518 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
04519 ** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
04520 ** the soft heap limit is enforced on every memory allocation.  Without
04521 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
04522 ** when memory is allocated by the page cache.  Testing suggests that because
04523 ** the page cache is the predominate memory user in SQLite, most
04524 ** applications will achieve adequate soft heap limit enforcement without
04525 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
04526 **
04527 ** The circumstances under which SQLite will enforce the soft heap limit may
04528 ** changes in future releases of SQLite.
04529 */
04530 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
04531 
04532 /*
04533 ** CAPI3REF: Deprecated Soft Heap Limit Interface
04534 ** DEPRECATED
04535 **
04536 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
04537 ** interface.  This routine is provided for historical compatibility
04538 ** only.  All new applications should use the
04539 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
04540 */
04541 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
04542 
04543 
04544 /*
04545 ** CAPI3REF: Extract Metadata About A Column Of A Table
04546 **
04547 ** ^This routine returns metadata about a specific column of a specific
04548 ** database table accessible using the [database connection] handle
04549 ** passed as the first function argument.
04550 **
04551 ** ^The column is identified by the second, third and fourth parameters to
04552 ** this function. ^The second parameter is either the name of the database
04553 ** (i.e. "main", "temp", or an attached database) containing the specified
04554 ** table or NULL. ^If it is NULL, then all attached databases are searched
04555 ** for the table using the same algorithm used by the database engine to
04556 ** resolve unqualified table references.
04557 **
04558 ** ^The third and fourth parameters to this function are the table and column
04559 ** name of the desired column, respectively. Neither of these parameters
04560 ** may be NULL.
04561 **
04562 ** ^Metadata is returned by writing to the memory locations passed as the 5th
04563 ** and subsequent parameters to this function. ^Any of these arguments may be
04564 ** NULL, in which case the corresponding element of metadata is omitted.
04565 **
04566 ** ^(<blockquote>
04567 ** <table border="1">
04568 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
04569 **
04570 ** <tr><td> 5th <td> const char* <td> Data type
04571 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
04572 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
04573 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
04574 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
04575 ** </table>
04576 ** </blockquote>)^
04577 **
04578 ** ^The memory pointed to by the character pointers returned for the
04579 ** declaration type and collation sequence is valid only until the next
04580 ** call to any SQLite API function.
04581 **
04582 ** ^If the specified table is actually a view, an [error code] is returned.
04583 **
04584 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
04585 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
04586 ** parameters are set for the explicitly declared column. ^(If there is no
04587 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
04588 ** parameters are set as follows:
04589 **
04590 ** <pre>
04591 **     data type: "INTEGER"
04592 **     collation sequence: "BINARY"
04593 **     not null: 0
04594 **     primary key: 1
04595 **     auto increment: 0
04596 ** </pre>)^
04597 **
04598 ** ^(This function may load one or more schemas from database files. If an
04599 ** error occurs during this process, or if the requested table or column
04600 ** cannot be found, an [error code] is returned and an error message left
04601 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
04602 **
04603 ** ^This API is only available if the library was compiled with the
04604 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
04605 */
04606 SQLITE_API int sqlite3_table_column_metadata(
04607   sqlite3 *db,                /* Connection handle */
04608   const char *zDbName,        /* Database name or NULL */
04609   const char *zTableName,     /* Table name */
04610   const char *zColumnName,    /* Column name */
04611   char const **pzDataType,    /* OUTPUT: Declared data type */
04612   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
04613   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
04614   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
04615   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
04616 );
04617 
04618 /*
04619 ** CAPI3REF: Load An Extension
04620 **
04621 ** ^This interface loads an SQLite extension library from the named file.
04622 **
04623 ** ^The sqlite3_load_extension() interface attempts to load an
04624 ** SQLite extension library contained in the file zFile.
04625 **
04626 ** ^The entry point is zProc.
04627 ** ^zProc may be 0, in which case the name of the entry point
04628 ** defaults to "sqlite3_extension_init".
04629 ** ^The sqlite3_load_extension() interface returns
04630 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
04631 ** ^If an error occurs and pzErrMsg is not 0, then the
04632 ** [sqlite3_load_extension()] interface shall attempt to
04633 ** fill *pzErrMsg with error message text stored in memory
04634 ** obtained from [sqlite3_malloc()]. The calling function
04635 ** should free this memory by calling [sqlite3_free()].
04636 **
04637 ** ^Extension loading must be enabled using
04638 ** [sqlite3_enable_load_extension()] prior to calling this API,
04639 ** otherwise an error will be returned.
04640 **
04641 ** See also the [load_extension() SQL function].
04642 */
04643 SQLITE_API int sqlite3_load_extension(
04644   sqlite3 *db,          /* Load the extension into this database connection */
04645   const char *zFile,    /* Name of the shared library containing extension */
04646   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
04647   char **pzErrMsg       /* Put error message here if not 0 */
04648 );
04649 
04650 /*
04651 ** CAPI3REF: Enable Or Disable Extension Loading
04652 **
04653 ** ^So as not to open security holes in older applications that are
04654 ** unprepared to deal with extension loading, and as a means of disabling
04655 ** extension loading while evaluating user-entered SQL, the following API
04656 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
04657 **
04658 ** ^Extension loading is off by default. See ticket #1863.
04659 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
04660 ** to turn extension loading on and call it with onoff==0 to turn
04661 ** it back off again.
04662 */
04663 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
04664 
04665 /*
04666 ** CAPI3REF: Automatically Load Statically Linked Extensions
04667 **
04668 ** ^This interface causes the xEntryPoint() function to be invoked for
04669 ** each new [database connection] that is created.  The idea here is that
04670 ** xEntryPoint() is the entry point for a statically linked SQLite extension
04671 ** that is to be automatically loaded into all new database connections.
04672 **
04673 ** ^(Even though the function prototype shows that xEntryPoint() takes
04674 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
04675 ** arguments and expects and integer result as if the signature of the
04676 ** entry point where as follows:
04677 **
04678 ** <blockquote><pre>
04679 ** &nbsp;  int xEntryPoint(
04680 ** &nbsp;    sqlite3 *db,
04681 ** &nbsp;    const char **pzErrMsg,
04682 ** &nbsp;    const struct sqlite3_api_routines *pThunk
04683 ** &nbsp;  );
04684 ** </pre></blockquote>)^
04685 **
04686 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
04687 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
04688 ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
04689 ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
04690 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
04691 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
04692 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
04693 **
04694 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
04695 ** on the list of automatic extensions is a harmless no-op. ^No entry point
04696 ** will be called more than once for each database connection that is opened.
04697 **
04698 ** See also: [sqlite3_reset_auto_extension()].
04699 */
04700 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
04701 
04702 /*
04703 ** CAPI3REF: Reset Automatic Extension Loading
04704 **
04705 ** ^This interface disables all automatic extensions previously
04706 ** registered using [sqlite3_auto_extension()].
04707 */
04708 SQLITE_API void sqlite3_reset_auto_extension(void);
04709 
04710 /*
04711 ** The interface to the virtual-table mechanism is currently considered
04712 ** to be experimental.  The interface might change in incompatible ways.
04713 ** If this is a problem for you, do not use the interface at this time.
04714 **
04715 ** When the virtual-table mechanism stabilizes, we will declare the
04716 ** interface fixed, support it indefinitely, and remove this comment.
04717 */
04718 
04719 /*
04720 ** Structures used by the virtual table interface
04721 */
04722 typedef struct sqlite3_vtab sqlite3_vtab;
04723 typedef struct sqlite3_index_info sqlite3_index_info;
04724 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
04725 typedef struct sqlite3_module sqlite3_module;
04726 
04727 /*
04728 ** CAPI3REF: Virtual Table Object
04729 ** KEYWORDS: sqlite3_module {virtual table module}
04730 **
04731 ** This structure, sometimes called a "virtual table module", 
04732 ** defines the implementation of a [virtual tables].  
04733 ** This structure consists mostly of methods for the module.
04734 **
04735 ** ^A virtual table module is created by filling in a persistent
04736 ** instance of this structure and passing a pointer to that instance
04737 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
04738 ** ^The registration remains valid until it is replaced by a different
04739 ** module or until the [database connection] closes.  The content
04740 ** of this structure must not change while it is registered with
04741 ** any database connection.
04742 */
04743 struct sqlite3_module {
04744   int iVersion;
04745   int (*xCreate)(sqlite3*, void *pAux,
04746                int argc, const char *const*argv,
04747                sqlite3_vtab **ppVTab, char**);
04748   int (*xConnect)(sqlite3*, void *pAux,
04749                int argc, const char *const*argv,
04750                sqlite3_vtab **ppVTab, char**);
04751   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
04752   int (*xDisconnect)(sqlite3_vtab *pVTab);
04753   int (*xDestroy)(sqlite3_vtab *pVTab);
04754   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
04755   int (*xClose)(sqlite3_vtab_cursor*);
04756   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
04757                 int argc, sqlite3_value **argv);
04758   int (*xNext)(sqlite3_vtab_cursor*);
04759   int (*xEof)(sqlite3_vtab_cursor*);
04760   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
04761   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
04762   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
04763   int (*xBegin)(sqlite3_vtab *pVTab);
04764   int (*xSync)(sqlite3_vtab *pVTab);
04765   int (*xCommit)(sqlite3_vtab *pVTab);
04766   int (*xRollback)(sqlite3_vtab *pVTab);
04767   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
04768                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
04769                        void **ppArg);
04770   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
04771   /* The methods above are in version 1 of the sqlite_module object. Those 
04772   ** below are for version 2 and greater. */
04773   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
04774   int (*xRelease)(sqlite3_vtab *pVTab, int);
04775   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
04776 };
04777 
04778 /*
04779 ** CAPI3REF: Virtual Table Indexing Information
04780 ** KEYWORDS: sqlite3_index_info
04781 **
04782 ** The sqlite3_index_info structure and its substructures is used as part
04783 ** of the [virtual table] interface to
04784 ** pass information into and receive the reply from the [xBestIndex]
04785 ** method of a [virtual table module].  The fields under **Inputs** are the
04786 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
04787 ** results into the **Outputs** fields.
04788 **
04789 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
04790 **
04791 ** <blockquote>column OP expr</blockquote>
04792 **
04793 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
04794 ** stored in aConstraint[].op using one of the
04795 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
04796 ** ^(The index of the column is stored in
04797 ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
04798 ** expr on the right-hand side can be evaluated (and thus the constraint
04799 ** is usable) and false if it cannot.)^
04800 **
04801 ** ^The optimizer automatically inverts terms of the form "expr OP column"
04802 ** and makes other simplifications to the WHERE clause in an attempt to
04803 ** get as many WHERE clause terms into the form shown above as possible.
04804 ** ^The aConstraint[] array only reports WHERE clause terms that are
04805 ** relevant to the particular virtual table being queried.
04806 **
04807 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
04808 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
04809 **
04810 ** The [xBestIndex] method must fill aConstraintUsage[] with information
04811 ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
04812 ** the right-hand side of the corresponding aConstraint[] is evaluated
04813 ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
04814 ** is true, then the constraint is assumed to be fully handled by the
04815 ** virtual table and is not checked again by SQLite.)^
04816 **
04817 ** ^The idxNum and idxPtr values are recorded and passed into the
04818 ** [xFilter] method.
04819 ** ^[sqlite3_free()] is used to free idxPtr if and only if
04820 ** needToFreeIdxPtr is true.
04821 **
04822 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
04823 ** the correct order to satisfy the ORDER BY clause so that no separate
04824 ** sorting step is required.
04825 **
04826 ** ^The estimatedCost value is an estimate of the cost of doing the
04827 ** particular lookup.  A full scan of a table with N entries should have
04828 ** a cost of N.  A binary search of a table of N entries should have a
04829 ** cost of approximately log(N).
04830 */
04831 struct sqlite3_index_info {
04832   /* Inputs */
04833   int nConstraint;           /* Number of entries in aConstraint */
04834   struct sqlite3_index_constraint {
04835      int iColumn;              /* Column on left-hand side of constraint */
04836      unsigned char op;         /* Constraint operator */
04837      unsigned char usable;     /* True if this constraint is usable */
04838      int iTermOffset;          /* Used internally - xBestIndex should ignore */
04839   } *aConstraint;            /* Table of WHERE clause constraints */
04840   int nOrderBy;              /* Number of terms in the ORDER BY clause */
04841   struct sqlite3_index_orderby {
04842      int iColumn;              /* Column number */
04843      unsigned char desc;       /* True for DESC.  False for ASC. */
04844   } *aOrderBy;               /* The ORDER BY clause */
04845   /* Outputs */
04846   struct sqlite3_index_constraint_usage {
04847     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
04848     unsigned char omit;      /* Do not code a test for this constraint */
04849   } *aConstraintUsage;
04850   int idxNum;                /* Number used to identify the index */
04851   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
04852   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
04853   int orderByConsumed;       /* True if output is already ordered */
04854   double estimatedCost;      /* Estimated cost of using this index */
04855 };
04856 
04857 /*
04858 ** CAPI3REF: Virtual Table Constraint Operator Codes
04859 **
04860 ** These macros defined the allowed values for the
04861 ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
04862 ** an operator that is part of a constraint term in the wHERE clause of
04863 ** a query that uses a [virtual table].
04864 */
04865 #define SQLITE_INDEX_CONSTRAINT_EQ    2
04866 #define SQLITE_INDEX_CONSTRAINT_GT    4
04867 #define SQLITE_INDEX_CONSTRAINT_LE    8
04868 #define SQLITE_INDEX_CONSTRAINT_LT    16
04869 #define SQLITE_INDEX_CONSTRAINT_GE    32
04870 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
04871 
04872 /*
04873 ** CAPI3REF: Register A Virtual Table Implementation
04874 **
04875 ** ^These routines are used to register a new [virtual table module] name.
04876 ** ^Module names must be registered before
04877 ** creating a new [virtual table] using the module and before using a
04878 ** preexisting [virtual table] for the module.
04879 **
04880 ** ^The module name is registered on the [database connection] specified
04881 ** by the first parameter.  ^The name of the module is given by the 
04882 ** second parameter.  ^The third parameter is a pointer to
04883 ** the implementation of the [virtual table module].   ^The fourth
04884 ** parameter is an arbitrary client data pointer that is passed through
04885 ** into the [xCreate] and [xConnect] methods of the virtual table module
04886 ** when a new virtual table is be being created or reinitialized.
04887 **
04888 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
04889 ** is a pointer to a destructor for the pClientData.  ^SQLite will
04890 ** invoke the destructor function (if it is not NULL) when SQLite
04891 ** no longer needs the pClientData pointer.  ^The destructor will also
04892 ** be invoked if the call to sqlite3_create_module_v2() fails.
04893 ** ^The sqlite3_create_module()
04894 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
04895 ** destructor.
04896 */
04897 SQLITE_API int sqlite3_create_module(
04898   sqlite3 *db,               /* SQLite connection to register module with */
04899   const char *zName,         /* Name of the module */
04900   const sqlite3_module *p,   /* Methods for the module */
04901   void *pClientData          /* Client data for xCreate/xConnect */
04902 );
04903 SQLITE_API int sqlite3_create_module_v2(
04904   sqlite3 *db,               /* SQLite connection to register module with */
04905   const char *zName,         /* Name of the module */
04906   const sqlite3_module *p,   /* Methods for the module */
04907   void *pClientData,         /* Client data for xCreate/xConnect */
04908   void(*xDestroy)(void*)     /* Module destructor function */
04909 );
04910 
04911 /*
04912 ** CAPI3REF: Virtual Table Instance Object
04913 ** KEYWORDS: sqlite3_vtab
04914 **
04915 ** Every [virtual table module] implementation uses a subclass
04916 ** of this object to describe a particular instance
04917 ** of the [virtual table].  Each subclass will
04918 ** be tailored to the specific needs of the module implementation.
04919 ** The purpose of this superclass is to define certain fields that are
04920 ** common to all module implementations.
04921 **
04922 ** ^Virtual tables methods can set an error message by assigning a
04923 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
04924 ** take care that any prior string is freed by a call to [sqlite3_free()]
04925 ** prior to assigning a new string to zErrMsg.  ^After the error message
04926 ** is delivered up to the client application, the string will be automatically
04927 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
04928 */
04929 struct sqlite3_vtab {
04930   const sqlite3_module *pModule;  /* The module for this virtual table */
04931   int nRef;                       /* NO LONGER USED */
04932   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
04933   /* Virtual table implementations will typically add additional fields */
04934 };
04935 
04936 /*
04937 ** CAPI3REF: Virtual Table Cursor Object
04938 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
04939 **
04940 ** Every [virtual table module] implementation uses a subclass of the
04941 ** following structure to describe cursors that point into the
04942 ** [virtual table] and are used
04943 ** to loop through the virtual table.  Cursors are created using the
04944 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
04945 ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
04946 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
04947 ** of the module.  Each module implementation will define
04948 ** the content of a cursor structure to suit its own needs.
04949 **
04950 ** This superclass exists in order to define fields of the cursor that
04951 ** are common to all implementations.
04952 */
04953 struct sqlite3_vtab_cursor {
04954   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
04955   /* Virtual table implementations will typically add additional fields */
04956 };
04957 
04958 /*
04959 ** CAPI3REF: Declare The Schema Of A Virtual Table
04960 **
04961 ** ^The [xCreate] and [xConnect] methods of a
04962 ** [virtual table module] call this interface
04963 ** to declare the format (the names and datatypes of the columns) of
04964 ** the virtual tables they implement.
04965 */
04966 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
04967 
04968 /*
04969 ** CAPI3REF: Overload A Function For A Virtual Table
04970 **
04971 ** ^(Virtual tables can provide alternative implementations of functions
04972 ** using the [xFindFunction] method of the [virtual table module].  
04973 ** But global versions of those functions
04974 ** must exist in order to be overloaded.)^
04975 **
04976 ** ^(This API makes sure a global version of a function with a particular
04977 ** name and number of parameters exists.  If no such function exists
04978 ** before this API is called, a new function is created.)^  ^The implementation
04979 ** of the new function always causes an exception to be thrown.  So
04980 ** the new function is not good for anything by itself.  Its only
04981 ** purpose is to be a placeholder function that can be overloaded
04982 ** by a [virtual table].
04983 */
04984 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
04985 
04986 /*
04987 ** The interface to the virtual-table mechanism defined above (back up
04988 ** to a comment remarkably similar to this one) is currently considered
04989 ** to be experimental.  The interface might change in incompatible ways.
04990 ** If this is a problem for you, do not use the interface at this time.
04991 **
04992 ** When the virtual-table mechanism stabilizes, we will declare the
04993 ** interface fixed, support it indefinitely, and remove this comment.
04994 */
04995 
04996 /*
04997 ** CAPI3REF: A Handle To An Open BLOB
04998 ** KEYWORDS: {BLOB handle} {BLOB handles}
04999 **
05000 ** An instance of this object represents an open BLOB on which
05001 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
05002 ** ^Objects of this type are created by [sqlite3_blob_open()]
05003 ** and destroyed by [sqlite3_blob_close()].
05004 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
05005 ** can be used to read or write small subsections of the BLOB.
05006 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
05007 */
05008 typedef struct sqlite3_blob sqlite3_blob;
05009 
05010 /*
05011 ** CAPI3REF: Open A BLOB For Incremental I/O
05012 **
05013 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
05014 ** in row iRow, column zColumn, table zTable in database zDb;
05015 ** in other words, the same BLOB that would be selected by:
05016 **
05017 ** <pre>
05018 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
05019 ** </pre>)^
05020 **
05021 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
05022 ** and write access. ^If it is zero, the BLOB is opened for read access.
05023 ** ^It is not possible to open a column that is part of an index or primary 
05024 ** key for writing. ^If [foreign key constraints] are enabled, it is 
05025 ** not possible to open a column that is part of a [child key] for writing.
05026 **
05027 ** ^Note that the database name is not the filename that contains
05028 ** the database but rather the symbolic name of the database that
05029 ** appears after the AS keyword when the database is connected using [ATTACH].
05030 ** ^For the main database file, the database name is "main".
05031 ** ^For TEMP tables, the database name is "temp".
05032 **
05033 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
05034 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
05035 ** to be a null pointer.)^
05036 ** ^This function sets the [database connection] error code and message
05037 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
05038 ** functions. ^Note that the *ppBlob variable is always initialized in a
05039 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
05040 ** regardless of the success or failure of this routine.
05041 **
05042 ** ^(If the row that a BLOB handle points to is modified by an
05043 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
05044 ** then the BLOB handle is marked as "expired".
05045 ** This is true if any column of the row is changed, even a column
05046 ** other than the one the BLOB handle is open on.)^
05047 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
05048 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
05049 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
05050 ** rolled back by the expiration of the BLOB.  Such changes will eventually
05051 ** commit if the transaction continues to completion.)^
05052 **
05053 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
05054 ** the opened blob.  ^The size of a blob may not be changed by this
05055 ** interface.  Use the [UPDATE] SQL command to change the size of a
05056 ** blob.
05057 **
05058 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
05059 ** and the built-in [zeroblob] SQL function can be used, if desired,
05060 ** to create an empty, zero-filled blob in which to read or write using
05061 ** this interface.
05062 **
05063 ** To avoid a resource leak, every open [BLOB handle] should eventually
05064 ** be released by a call to [sqlite3_blob_close()].
05065 */
05066 SQLITE_API int sqlite3_blob_open(
05067   sqlite3*,
05068   const char *zDb,
05069   const char *zTable,
05070   const char *zColumn,
05071   sqlite3_int64 iRow,
05072   int flags,
05073   sqlite3_blob **ppBlob
05074 );
05075 
05076 /*
05077 ** CAPI3REF: Move a BLOB Handle to a New Row
05078 **
05079 ** ^This function is used to move an existing blob handle so that it points
05080 ** to a different row of the same database table. ^The new row is identified
05081 ** by the rowid value passed as the second argument. Only the row can be
05082 ** changed. ^The database, table and column on which the blob handle is open
05083 ** remain the same. Moving an existing blob handle to a new row can be
05084 ** faster than closing the existing handle and opening a new one.
05085 **
05086 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
05087 ** it must exist and there must be either a blob or text value stored in
05088 ** the nominated column.)^ ^If the new row is not present in the table, or if
05089 ** it does not contain a blob or text value, or if another error occurs, an
05090 ** SQLite error code is returned and the blob handle is considered aborted.
05091 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
05092 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
05093 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
05094 ** always returns zero.
05095 **
05096 ** ^This function sets the database handle error code and message.
05097 */
05098 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
05099 
05100 /*
05101 ** CAPI3REF: Close A BLOB Handle
05102 **
05103 ** ^Closes an open [BLOB handle].
05104 **
05105 ** ^Closing a BLOB shall cause the current transaction to commit
05106 ** if there are no other BLOBs, no pending prepared statements, and the
05107 ** database connection is in [autocommit mode].
05108 ** ^If any writes were made to the BLOB, they might be held in cache
05109 ** until the close operation if they will fit.
05110 **
05111 ** ^(Closing the BLOB often forces the changes
05112 ** out to disk and so if any I/O errors occur, they will likely occur
05113 ** at the time when the BLOB is closed.  Any errors that occur during
05114 ** closing are reported as a non-zero return value.)^
05115 **
05116 ** ^(The BLOB is closed unconditionally.  Even if this routine returns
05117 ** an error code, the BLOB is still closed.)^
05118 **
05119 ** ^Calling this routine with a null pointer (such as would be returned
05120 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
05121 */
05122 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
05123 
05124 /*
05125 ** CAPI3REF: Return The Size Of An Open BLOB
05126 **
05127 ** ^Returns the size in bytes of the BLOB accessible via the 
05128 ** successfully opened [BLOB handle] in its only argument.  ^The
05129 ** incremental blob I/O routines can only read or overwriting existing
05130 ** blob content; they cannot change the size of a blob.
05131 **
05132 ** This routine only works on a [BLOB handle] which has been created
05133 ** by a prior successful call to [sqlite3_blob_open()] and which has not
05134 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
05135 ** to this routine results in undefined and probably undesirable behavior.
05136 */
05137 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
05138 
05139 /*
05140 ** CAPI3REF: Read Data From A BLOB Incrementally
05141 **
05142 ** ^(This function is used to read data from an open [BLOB handle] into a
05143 ** caller-supplied buffer. N bytes of data are copied into buffer Z
05144 ** from the open BLOB, starting at offset iOffset.)^
05145 **
05146 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
05147 ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
05148 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
05149 ** ^The size of the blob (and hence the maximum value of N+iOffset)
05150 ** can be determined using the [sqlite3_blob_bytes()] interface.
05151 **
05152 ** ^An attempt to read from an expired [BLOB handle] fails with an
05153 ** error code of [SQLITE_ABORT].
05154 **
05155 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
05156 ** Otherwise, an [error code] or an [extended error code] is returned.)^
05157 **
05158 ** This routine only works on a [BLOB handle] which has been created
05159 ** by a prior successful call to [sqlite3_blob_open()] and which has not
05160 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
05161 ** to this routine results in undefined and probably undesirable behavior.
05162 **
05163 ** See also: [sqlite3_blob_write()].
05164 */
05165 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
05166 
05167 /*
05168 ** CAPI3REF: Write Data Into A BLOB Incrementally
05169 **
05170 ** ^This function is used to write data into an open [BLOB handle] from a
05171 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
05172 ** into the open BLOB, starting at offset iOffset.
05173 **
05174 ** ^If the [BLOB handle] passed as the first argument was not opened for
05175 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
05176 ** this function returns [SQLITE_READONLY].
05177 **
05178 ** ^This function may only modify the contents of the BLOB; it is
05179 ** not possible to increase the size of a BLOB using this API.
05180 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
05181 ** [SQLITE_ERROR] is returned and no data is written.  ^If N is
05182 ** less than zero [SQLITE_ERROR] is returned and no data is written.
05183 ** The size of the BLOB (and hence the maximum value of N+iOffset)
05184 ** can be determined using the [sqlite3_blob_bytes()] interface.
05185 **
05186 ** ^An attempt to write to an expired [BLOB handle] fails with an
05187 ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
05188 ** before the [BLOB handle] expired are not rolled back by the
05189 ** expiration of the handle, though of course those changes might
05190 ** have been overwritten by the statement that expired the BLOB handle
05191 ** or by other independent statements.
05192 **
05193 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
05194 ** Otherwise, an  [error code] or an [extended error code] is returned.)^
05195 **
05196 ** This routine only works on a [BLOB handle] which has been created
05197 ** by a prior successful call to [sqlite3_blob_open()] and which has not
05198 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
05199 ** to this routine results in undefined and probably undesirable behavior.
05200 **
05201 ** See also: [sqlite3_blob_read()].
05202 */
05203 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
05204 
05205 /*
05206 ** CAPI3REF: Virtual File System Objects
05207 **
05208 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
05209 ** that SQLite uses to interact
05210 ** with the underlying operating system.  Most SQLite builds come with a
05211 ** single default VFS that is appropriate for the host computer.
05212 ** New VFSes can be registered and existing VFSes can be unregistered.
05213 ** The following interfaces are provided.
05214 **
05215 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
05216 ** ^Names are case sensitive.
05217 ** ^Names are zero-terminated UTF-8 strings.
05218 ** ^If there is no match, a NULL pointer is returned.
05219 ** ^If zVfsName is NULL then the default VFS is returned.
05220 **
05221 ** ^New VFSes are registered with sqlite3_vfs_register().
05222 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
05223 ** ^The same VFS can be registered multiple times without injury.
05224 ** ^To make an existing VFS into the default VFS, register it again
05225 ** with the makeDflt flag set.  If two different VFSes with the
05226 ** same name are registered, the behavior is undefined.  If a
05227 ** VFS is registered with a name that is NULL or an empty string,
05228 ** then the behavior is undefined.
05229 **
05230 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
05231 ** ^(If the default VFS is unregistered, another VFS is chosen as
05232 ** the default.  The choice for the new VFS is arbitrary.)^
05233 */
05234 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
05235 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
05236 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
05237 
05238 /*
05239 ** CAPI3REF: Mutexes
05240 **
05241 ** The SQLite core uses these routines for thread
05242 ** synchronization. Though they are intended for internal
05243 ** use by SQLite, code that links against SQLite is
05244 ** permitted to use any of these routines.
05245 **
05246 ** The SQLite source code contains multiple implementations
05247 ** of these mutex routines.  An appropriate implementation
05248 ** is selected automatically at compile-time.  ^(The following
05249 ** implementations are available in the SQLite core:
05250 **
05251 ** <ul>
05252 ** <li>   SQLITE_MUTEX_OS2
05253 ** <li>   SQLITE_MUTEX_PTHREAD
05254 ** <li>   SQLITE_MUTEX_W32
05255 ** <li>   SQLITE_MUTEX_NOOP
05256 ** </ul>)^
05257 **
05258 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
05259 ** that does no real locking and is appropriate for use in
05260 ** a single-threaded application.  ^The SQLITE_MUTEX_OS2,
05261 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
05262 ** are appropriate for use on OS/2, Unix, and Windows.
05263 **
05264 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
05265 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
05266 ** implementation is included with the library. In this case the
05267 ** application must supply a custom mutex implementation using the
05268 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
05269 ** before calling sqlite3_initialize() or any other public sqlite3_
05270 ** function that calls sqlite3_initialize().)^
05271 **
05272 ** ^The sqlite3_mutex_alloc() routine allocates a new
05273 ** mutex and returns a pointer to it. ^If it returns NULL
05274 ** that means that a mutex could not be allocated.  ^SQLite
05275 ** will unwind its stack and return an error.  ^(The argument
05276 ** to sqlite3_mutex_alloc() is one of these integer constants:
05277 **
05278 ** <ul>
05279 ** <li>  SQLITE_MUTEX_FAST
05280 ** <li>  SQLITE_MUTEX_RECURSIVE
05281 ** <li>  SQLITE_MUTEX_STATIC_MASTER
05282 ** <li>  SQLITE_MUTEX_STATIC_MEM
05283 ** <li>  SQLITE_MUTEX_STATIC_MEM2
05284 ** <li>  SQLITE_MUTEX_STATIC_PRNG
05285 ** <li>  SQLITE_MUTEX_STATIC_LRU
05286 ** <li>  SQLITE_MUTEX_STATIC_LRU2
05287 ** </ul>)^
05288 **
05289 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
05290 ** cause sqlite3_mutex_alloc() to create
05291 ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
05292 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
05293 ** The mutex implementation does not need to make a distinction
05294 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
05295 ** not want to.  ^SQLite will only request a recursive mutex in
05296 ** cases where it really needs one.  ^If a faster non-recursive mutex
05297 ** implementation is available on the host platform, the mutex subsystem
05298 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
05299 **
05300 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
05301 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
05302 ** a pointer to a static preexisting mutex.  ^Six static mutexes are
05303 ** used by the current version of SQLite.  Future versions of SQLite
05304 ** may add additional static mutexes.  Static mutexes are for internal
05305 ** use by SQLite only.  Applications that use SQLite mutexes should
05306 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
05307 ** SQLITE_MUTEX_RECURSIVE.
05308 **
05309 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
05310 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
05311 ** returns a different mutex on every call.  ^But for the static
05312 ** mutex types, the same mutex is returned on every call that has
05313 ** the same type number.
05314 **
05315 ** ^The sqlite3_mutex_free() routine deallocates a previously
05316 ** allocated dynamic mutex.  ^SQLite is careful to deallocate every
05317 ** dynamic mutex that it allocates.  The dynamic mutexes must not be in
05318 ** use when they are deallocated.  Attempting to deallocate a static
05319 ** mutex results in undefined behavior.  ^SQLite never deallocates
05320 ** a static mutex.
05321 **
05322 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
05323 ** to enter a mutex.  ^If another thread is already within the mutex,
05324 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
05325 ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
05326 ** upon successful entry.  ^(Mutexes created using
05327 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
05328 ** In such cases the,
05329 ** mutex must be exited an equal number of times before another thread
05330 ** can enter.)^  ^(If the same thread tries to enter any other
05331 ** kind of mutex more than once, the behavior is undefined.
05332 ** SQLite will never exhibit
05333 ** such behavior in its own use of mutexes.)^
05334 **
05335 ** ^(Some systems (for example, Windows 95) do not support the operation
05336 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
05337 ** will always return SQLITE_BUSY.  The SQLite core only ever uses
05338 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
05339 **
05340 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
05341 ** previously entered by the same thread.   ^(The behavior
05342 ** is undefined if the mutex is not currently entered by the
05343 ** calling thread or is not currently allocated.  SQLite will
05344 ** never do either.)^
05345 **
05346 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
05347 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
05348 ** behave as no-ops.
05349 **
05350 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
05351 */
05352 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
05353 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
05354 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
05355 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
05356 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
05357 
05358 /*
05359 ** CAPI3REF: Mutex Methods Object
05360 **
05361 ** An instance of this structure defines the low-level routines
05362 ** used to allocate and use mutexes.
05363 **
05364 ** Usually, the default mutex implementations provided by SQLite are
05365 ** sufficient, however the user has the option of substituting a custom
05366 ** implementation for specialized deployments or systems for which SQLite
05367 ** does not provide a suitable implementation. In this case, the user
05368 ** creates and populates an instance of this structure to pass
05369 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
05370 ** Additionally, an instance of this structure can be used as an
05371 ** output variable when querying the system for the current mutex
05372 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
05373 **
05374 ** ^The xMutexInit method defined by this structure is invoked as
05375 ** part of system initialization by the sqlite3_initialize() function.
05376 ** ^The xMutexInit routine is called by SQLite exactly once for each
05377 ** effective call to [sqlite3_initialize()].
05378 **
05379 ** ^The xMutexEnd method defined by this structure is invoked as
05380 ** part of system shutdown by the sqlite3_shutdown() function. The
05381 ** implementation of this method is expected to release all outstanding
05382 ** resources obtained by the mutex methods implementation, especially
05383 ** those obtained by the xMutexInit method.  ^The xMutexEnd()
05384 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
05385 **
05386 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
05387 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
05388 ** xMutexNotheld) implement the following interfaces (respectively):
05389 **
05390 ** <ul>
05391 **   <li>  [sqlite3_mutex_alloc()] </li>
05392 **   <li>  [sqlite3_mutex_free()] </li>
05393 **   <li>  [sqlite3_mutex_enter()] </li>
05394 **   <li>  [sqlite3_mutex_try()] </li>
05395 **   <li>  [sqlite3_mutex_leave()] </li>
05396 **   <li>  [sqlite3_mutex_held()] </li>
05397 **   <li>  [sqlite3_mutex_notheld()] </li>
05398 ** </ul>)^
05399 **
05400 ** The only difference is that the public sqlite3_XXX functions enumerated
05401 ** above silently ignore any invocations that pass a NULL pointer instead
05402 ** of a valid mutex handle. The implementations of the methods defined
05403 ** by this structure are not required to handle this case, the results
05404 ** of passing a NULL pointer instead of a valid mutex handle are undefined
05405 ** (i.e. it is acceptable to provide an implementation that segfaults if
05406 ** it is passed a NULL pointer).
05407 **
05408 ** The xMutexInit() method must be threadsafe.  ^It must be harmless to
05409 ** invoke xMutexInit() multiple times within the same process and without
05410 ** intervening calls to xMutexEnd().  Second and subsequent calls to
05411 ** xMutexInit() must be no-ops.
05412 **
05413 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
05414 ** and its associates).  ^Similarly, xMutexAlloc() must not use SQLite memory
05415 ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
05416 ** memory allocation for a fast or recursive mutex.
05417 **
05418 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
05419 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
05420 ** If xMutexInit fails in any way, it is expected to clean up after itself
05421 ** prior to returning.
05422 */
05423 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
05424 struct sqlite3_mutex_methods {
05425   int (*xMutexInit)(void);
05426   int (*xMutexEnd)(void);
05427   sqlite3_mutex *(*xMutexAlloc)(int);
05428   void (*xMutexFree)(sqlite3_mutex *);
05429   void (*xMutexEnter)(sqlite3_mutex *);
05430   int (*xMutexTry)(sqlite3_mutex *);
05431   void (*xMutexLeave)(sqlite3_mutex *);
05432   int (*xMutexHeld)(sqlite3_mutex *);
05433   int (*xMutexNotheld)(sqlite3_mutex *);
05434 };
05435 
05436 /*
05437 ** CAPI3REF: Mutex Verification Routines
05438 **
05439 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
05440 ** are intended for use inside assert() statements.  ^The SQLite core
05441 ** never uses these routines except inside an assert() and applications
05442 ** are advised to follow the lead of the core.  ^The SQLite core only
05443 ** provides implementations for these routines when it is compiled
05444 ** with the SQLITE_DEBUG flag.  ^External mutex implementations
05445 ** are only required to provide these routines if SQLITE_DEBUG is
05446 ** defined and if NDEBUG is not defined.
05447 **
05448 ** ^These routines should return true if the mutex in their argument
05449 ** is held or not held, respectively, by the calling thread.
05450 **
05451 ** ^The implementation is not required to provided versions of these
05452 ** routines that actually work. If the implementation does not provide working
05453 ** versions of these routines, it should at least provide stubs that always
05454 ** return true so that one does not get spurious assertion failures.
05455 **
05456 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
05457 ** the routine should return 1.   This seems counter-intuitive since
05458 ** clearly the mutex cannot be held if it does not exist.  But
05459 ** the reason the mutex does not exist is because the build is not
05460 ** using mutexes.  And we do not want the assert() containing the
05461 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
05462 ** the appropriate thing to do.  ^The sqlite3_mutex_notheld()
05463 ** interface should also return 1 when given a NULL pointer.
05464 */
05465 #ifndef NDEBUG
05466 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
05467 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
05468 #endif
05469 
05470 /*
05471 ** CAPI3REF: Mutex Types
05472 **
05473 ** The [sqlite3_mutex_alloc()] interface takes a single argument
05474 ** which is one of these integer constants.
05475 **
05476 ** The set of static mutexes may change from one SQLite release to the
05477 ** next.  Applications that override the built-in mutex logic must be
05478 ** prepared to accommodate additional static mutexes.
05479 */
05480 #define SQLITE_MUTEX_FAST             0
05481 #define SQLITE_MUTEX_RECURSIVE        1
05482 #define SQLITE_MUTEX_STATIC_MASTER    2
05483 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
05484 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
05485 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
05486 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
05487 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
05488 #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
05489 #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
05490 
05491 /*
05492 ** CAPI3REF: Retrieve the mutex for a database connection
05493 **
05494 ** ^This interface returns a pointer the [sqlite3_mutex] object that 
05495 ** serializes access to the [database connection] given in the argument
05496 ** when the [threading mode] is Serialized.
05497 ** ^If the [threading mode] is Single-thread or Multi-thread then this
05498 ** routine returns a NULL pointer.
05499 */
05500 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
05501 
05502 /*
05503 ** CAPI3REF: Low-Level Control Of Database Files
05504 **
05505 ** ^The [sqlite3_file_control()] interface makes a direct call to the
05506 ** xFileControl method for the [sqlite3_io_methods] object associated
05507 ** with a particular database identified by the second argument. ^The
05508 ** name of the database is "main" for the main database or "temp" for the
05509 ** TEMP database, or the name that appears after the AS keyword for
05510 ** databases that are added using the [ATTACH] SQL command.
05511 ** ^A NULL pointer can be used in place of "main" to refer to the
05512 ** main database file.
05513 ** ^The third and fourth parameters to this routine
05514 ** are passed directly through to the second and third parameters of
05515 ** the xFileControl method.  ^The return value of the xFileControl
05516 ** method becomes the return value of this routine.
05517 **
05518 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
05519 ** a pointer to the underlying [sqlite3_file] object to be written into
05520 ** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
05521 ** case is a short-circuit path which does not actually invoke the
05522 ** underlying sqlite3_io_methods.xFileControl method.
05523 **
05524 ** ^If the second parameter (zDbName) does not match the name of any
05525 ** open database file, then SQLITE_ERROR is returned.  ^This error
05526 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
05527 ** or [sqlite3_errmsg()].  The underlying xFileControl method might
05528 ** also return SQLITE_ERROR.  There is no way to distinguish between
05529 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
05530 ** xFileControl method.
05531 **
05532 ** See also: [SQLITE_FCNTL_LOCKSTATE]
05533 */
05534 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
05535 
05536 /*
05537 ** CAPI3REF: Testing Interface
05538 **
05539 ** ^The sqlite3_test_control() interface is used to read out internal
05540 ** state of SQLite and to inject faults into SQLite for testing
05541 ** purposes.  ^The first parameter is an operation code that determines
05542 ** the number, meaning, and operation of all subsequent parameters.
05543 **
05544 ** This interface is not for use by applications.  It exists solely
05545 ** for verifying the correct operation of the SQLite library.  Depending
05546 ** on how the SQLite library is compiled, this interface might not exist.
05547 **
05548 ** The details of the operation codes, their meanings, the parameters
05549 ** they take, and what they do are all subject to change without notice.
05550 ** Unlike most of the SQLite API, this function is not guaranteed to
05551 ** operate consistently from one release to the next.
05552 */
05553 SQLITE_API int sqlite3_test_control(int op, ...);
05554 
05555 /*
05556 ** CAPI3REF: Testing Interface Operation Codes
05557 **
05558 ** These constants are the valid operation code parameters used
05559 ** as the first argument to [sqlite3_test_control()].
05560 **
05561 ** These parameters and their meanings are subject to change
05562 ** without notice.  These values are for testing purposes only.
05563 ** Applications should not use any of these parameters or the
05564 ** [sqlite3_test_control()] interface.
05565 */
05566 #define SQLITE_TESTCTRL_FIRST                    5
05567 #define SQLITE_TESTCTRL_PRNG_SAVE                5
05568 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
05569 #define SQLITE_TESTCTRL_PRNG_RESET               7
05570 #define SQLITE_TESTCTRL_BITVEC_TEST              8
05571 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
05572 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
05573 #define SQLITE_TESTCTRL_PENDING_BYTE            11
05574 #define SQLITE_TESTCTRL_ASSERT                  12
05575 #define SQLITE_TESTCTRL_ALWAYS                  13
05576 #define SQLITE_TESTCTRL_RESERVE                 14
05577 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
05578 #define SQLITE_TESTCTRL_ISKEYWORD               16
05579 #define SQLITE_TESTCTRL_PGHDRSZ                 17
05580 #define SQLITE_TESTCTRL_SCRATCHMALLOC           18
05581 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         19
05582 #define SQLITE_TESTCTRL_LAST                    19
05583 
05584 /*
05585 ** CAPI3REF: SQLite Runtime Status
05586 **
05587 ** ^This interface is used to retrieve runtime status information
05588 ** about the performance of SQLite, and optionally to reset various
05589 ** highwater marks.  ^The first argument is an integer code for
05590 ** the specific parameter to measure.  ^(Recognized integer codes
05591 ** are of the form [status parameters | SQLITE_STATUS_...].)^
05592 ** ^The current value of the parameter is returned into *pCurrent.
05593 ** ^The highest recorded value is returned in *pHighwater.  ^If the
05594 ** resetFlag is true, then the highest record value is reset after
05595 ** *pHighwater is written.  ^(Some parameters do not record the highest
05596 ** value.  For those parameters
05597 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
05598 ** ^(Other parameters record only the highwater mark and not the current
05599 ** value.  For these latter parameters nothing is written into *pCurrent.)^
05600 **
05601 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
05602 ** non-zero [error code] on failure.
05603 **
05604 ** This routine is threadsafe but is not atomic.  This routine can be
05605 ** called while other threads are running the same or different SQLite
05606 ** interfaces.  However the values returned in *pCurrent and
05607 ** *pHighwater reflect the status of SQLite at different points in time
05608 ** and it is possible that another thread might change the parameter
05609 ** in between the times when *pCurrent and *pHighwater are written.
05610 **
05611 ** See also: [sqlite3_db_status()]
05612 */
05613 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
05614 
05615 
05616 /*
05617 ** CAPI3REF: Status Parameters
05618 ** KEYWORDS: {status parameters}
05619 **
05620 ** These integer constants designate various run-time status parameters
05621 ** that can be returned by [sqlite3_status()].
05622 **
05623 ** <dl>
05624 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
05625 ** <dd>This parameter is the current amount of memory checked out
05626 ** using [sqlite3_malloc()], either directly or indirectly.  The
05627 ** figure includes calls made to [sqlite3_malloc()] by the application
05628 ** and internal memory usage by the SQLite library.  Scratch memory
05629 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
05630 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
05631 ** this parameter.  The amount returned is the sum of the allocation
05632 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
05633 **
05634 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
05635 ** <dd>This parameter records the largest memory allocation request
05636 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
05637 ** internal equivalents).  Only the value returned in the
05638 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
05639 ** The value written into the *pCurrent parameter is undefined.</dd>)^
05640 **
05641 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
05642 ** <dd>This parameter records the number of separate memory allocations
05643 ** currently checked out.</dd>)^
05644 **
05645 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
05646 ** <dd>This parameter returns the number of pages used out of the
05647 ** [pagecache memory allocator] that was configured using 
05648 ** [SQLITE_CONFIG_PAGECACHE].  The
05649 ** value returned is in pages, not in bytes.</dd>)^
05650 **
05651 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 
05652 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
05653 ** <dd>This parameter returns the number of bytes of page cache
05654 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
05655 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
05656 ** returned value includes allocations that overflowed because they
05657 ** where too large (they were larger than the "sz" parameter to
05658 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
05659 ** no space was left in the page cache.</dd>)^
05660 **
05661 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
05662 ** <dd>This parameter records the largest memory allocation request
05663 ** handed to [pagecache memory allocator].  Only the value returned in the
05664 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
05665 ** The value written into the *pCurrent parameter is undefined.</dd>)^
05666 **
05667 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
05668 ** <dd>This parameter returns the number of allocations used out of the
05669 ** [scratch memory allocator] configured using
05670 ** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
05671 ** in bytes.  Since a single thread may only have one scratch allocation
05672 ** outstanding at time, this parameter also reports the number of threads
05673 ** using scratch memory at the same time.</dd>)^
05674 **
05675 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
05676 ** <dd>This parameter returns the number of bytes of scratch memory
05677 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
05678 ** buffer and where forced to overflow to [sqlite3_malloc()].  The values
05679 ** returned include overflows because the requested allocation was too
05680 ** larger (that is, because the requested allocation was larger than the
05681 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
05682 ** slots were available.
05683 ** </dd>)^
05684 **
05685 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
05686 ** <dd>This parameter records the largest memory allocation request
05687 ** handed to [scratch memory allocator].  Only the value returned in the
05688 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
05689 ** The value written into the *pCurrent parameter is undefined.</dd>)^
05690 **
05691 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
05692 ** <dd>This parameter records the deepest parser stack.  It is only
05693 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
05694 ** </dl>
05695 **
05696 ** New status parameters may be added from time to time.
05697 */
05698 #define SQLITE_STATUS_MEMORY_USED          0
05699 #define SQLITE_STATUS_PAGECACHE_USED       1
05700 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
05701 #define SQLITE_STATUS_SCRATCH_USED         3
05702 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4
05703 #define SQLITE_STATUS_MALLOC_SIZE          5
05704 #define SQLITE_STATUS_PARSER_STACK         6
05705 #define SQLITE_STATUS_PAGECACHE_SIZE       7
05706 #define SQLITE_STATUS_SCRATCH_SIZE         8
05707 #define SQLITE_STATUS_MALLOC_COUNT         9
05708 
05709 /*
05710 ** CAPI3REF: Database Connection Status
05711 **
05712 ** ^This interface is used to retrieve runtime status information 
05713 ** about a single [database connection].  ^The first argument is the
05714 ** database connection object to be interrogated.  ^The second argument
05715 ** is an integer constant, taken from the set of
05716 ** [SQLITE_DBSTATUS options], that
05717 ** determines the parameter to interrogate.  The set of 
05718 ** [SQLITE_DBSTATUS options] is likely
05719 ** to grow in future releases of SQLite.
05720 **
05721 ** ^The current value of the requested parameter is written into *pCur
05722 ** and the highest instantaneous value is written into *pHiwtr.  ^If
05723 ** the resetFlg is true, then the highest instantaneous value is
05724 ** reset back down to the current value.
05725 **
05726 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
05727 ** non-zero [error code] on failure.
05728 **
05729 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
05730 */
05731 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
05732 
05733 /*
05734 ** CAPI3REF: Status Parameters for database connections
05735 ** KEYWORDS: {SQLITE_DBSTATUS options}
05736 **
05737 ** These constants are the available integer "verbs" that can be passed as
05738 ** the second argument to the [sqlite3_db_status()] interface.
05739 **
05740 ** New verbs may be added in future releases of SQLite. Existing verbs
05741 ** might be discontinued. Applications should check the return code from
05742 ** [sqlite3_db_status()] to make sure that the call worked.
05743 ** The [sqlite3_db_status()] interface will return a non-zero error code
05744 ** if a discontinued or unsupported verb is invoked.
05745 **
05746 ** <dl>
05747 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
05748 ** <dd>This parameter returns the number of lookaside memory slots currently
05749 ** checked out.</dd>)^
05750 **
05751 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
05752 ** <dd>This parameter returns the number malloc attempts that were 
05753 ** satisfied using lookaside memory. Only the high-water value is meaningful;
05754 ** the current value is always zero.)^
05755 **
05756 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
05757 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
05758 ** <dd>This parameter returns the number malloc attempts that might have
05759 ** been satisfied using lookaside memory but failed due to the amount of
05760 ** memory requested being larger than the lookaside slot size.
05761 ** Only the high-water value is meaningful;
05762 ** the current value is always zero.)^
05763 **
05764 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
05765 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
05766 ** <dd>This parameter returns the number malloc attempts that might have
05767 ** been satisfied using lookaside memory but failed due to all lookaside
05768 ** memory already being in use.
05769 ** Only the high-water value is meaningful;
05770 ** the current value is always zero.)^
05771 **
05772 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
05773 ** <dd>This parameter returns the approximate number of of bytes of heap
05774 ** memory used by all pager caches associated with the database connection.)^
05775 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
05776 **
05777 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
05778 ** <dd>This parameter returns the approximate number of of bytes of heap
05779 ** memory used to store the schema for all databases associated
05780 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 
05781 ** ^The full amount of memory used by the schemas is reported, even if the
05782 ** schema memory is shared with other database connections due to
05783 ** [shared cache mode] being enabled.
05784 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
05785 **
05786 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
05787 ** <dd>This parameter returns the approximate number of of bytes of heap
05788 ** and lookaside memory used by all prepared statements associated with
05789 ** the database connection.)^
05790 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
05791 ** </dd>
05792 ** </dl>
05793 */
05794 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
05795 #define SQLITE_DBSTATUS_CACHE_USED           1
05796 #define SQLITE_DBSTATUS_SCHEMA_USED          2
05797 #define SQLITE_DBSTATUS_STMT_USED            3
05798 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
05799 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
05800 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
05801 #define SQLITE_DBSTATUS_MAX                  6   /* Largest defined DBSTATUS */
05802 
05803 
05804 /*
05805 ** CAPI3REF: Prepared Statement Status
05806 **
05807 ** ^(Each prepared statement maintains various
05808 ** [SQLITE_STMTSTATUS counters] that measure the number
05809 ** of times it has performed specific operations.)^  These counters can
05810 ** be used to monitor the performance characteristics of the prepared
05811 ** statements.  For example, if the number of table steps greatly exceeds
05812 ** the number of table searches or result rows, that would tend to indicate
05813 ** that the prepared statement is using a full table scan rather than
05814 ** an index.  
05815 **
05816 ** ^(This interface is used to retrieve and reset counter values from
05817 ** a [prepared statement].  The first argument is the prepared statement
05818 ** object to be interrogated.  The second argument
05819 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
05820 ** to be interrogated.)^
05821 ** ^The current value of the requested counter is returned.
05822 ** ^If the resetFlg is true, then the counter is reset to zero after this
05823 ** interface call returns.
05824 **
05825 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
05826 */
05827 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
05828 
05829 /*
05830 ** CAPI3REF: Status Parameters for prepared statements
05831 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
05832 **
05833 ** These preprocessor macros define integer codes that name counter
05834 ** values associated with the [sqlite3_stmt_status()] interface.
05835 ** The meanings of the various counters are as follows:
05836 **
05837 ** <dl>
05838 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
05839 ** <dd>^This is the number of times that SQLite has stepped forward in
05840 ** a table as part of a full table scan.  Large numbers for this counter
05841 ** may indicate opportunities for performance improvement through 
05842 ** careful use of indices.</dd>
05843 **
05844 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
05845 ** <dd>^This is the number of sort operations that have occurred.
05846 ** A non-zero value in this counter may indicate an opportunity to
05847 ** improvement performance through careful use of indices.</dd>
05848 **
05849 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
05850 ** <dd>^This is the number of rows inserted into transient indices that
05851 ** were created automatically in order to help joins run faster.
05852 ** A non-zero value in this counter may indicate an opportunity to
05853 ** improvement performance by adding permanent indices that do not
05854 ** need to be reinitialized each time the statement is run.</dd>
05855 **
05856 ** </dl>
05857 */
05858 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
05859 #define SQLITE_STMTSTATUS_SORT              2
05860 #define SQLITE_STMTSTATUS_AUTOINDEX         3
05861 
05862 /*
05863 ** CAPI3REF: Custom Page Cache Object
05864 **
05865 ** The sqlite3_pcache type is opaque.  It is implemented by
05866 ** the pluggable module.  The SQLite core has no knowledge of
05867 ** its size or internal structure and never deals with the
05868 ** sqlite3_pcache object except by holding and passing pointers
05869 ** to the object.
05870 **
05871 ** See [sqlite3_pcache_methods] for additional information.
05872 */
05873 typedef struct sqlite3_pcache sqlite3_pcache;
05874 
05875 /*
05876 ** CAPI3REF: Application Defined Page Cache.
05877 ** KEYWORDS: {page cache}
05878 **
05879 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
05880 ** register an alternative page cache implementation by passing in an 
05881 ** instance of the sqlite3_pcache_methods structure.)^
05882 ** In many applications, most of the heap memory allocated by 
05883 ** SQLite is used for the page cache.
05884 ** By implementing a 
05885 ** custom page cache using this API, an application can better control
05886 ** the amount of memory consumed by SQLite, the way in which 
05887 ** that memory is allocated and released, and the policies used to 
05888 ** determine exactly which parts of a database file are cached and for 
05889 ** how long.
05890 **
05891 ** The alternative page cache mechanism is an
05892 ** extreme measure that is only needed by the most demanding applications.
05893 ** The built-in page cache is recommended for most uses.
05894 **
05895 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an
05896 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
05897 ** the application may discard the parameter after the call to
05898 ** [sqlite3_config()] returns.)^
05899 **
05900 ** [[the xInit() page cache method]]
05901 ** ^(The xInit() method is called once for each effective 
05902 ** call to [sqlite3_initialize()])^
05903 ** (usually only once during the lifetime of the process). ^(The xInit()
05904 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^
05905 ** The intent of the xInit() method is to set up global data structures 
05906 ** required by the custom page cache implementation. 
05907 ** ^(If the xInit() method is NULL, then the 
05908 ** built-in default page cache is used instead of the application defined
05909 ** page cache.)^
05910 **
05911 ** [[the xShutdown() page cache method]]
05912 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
05913 ** It can be used to clean up 
05914 ** any outstanding resources before process shutdown, if required.
05915 ** ^The xShutdown() method may be NULL.
05916 **
05917 ** ^SQLite automatically serializes calls to the xInit method,
05918 ** so the xInit method need not be threadsafe.  ^The
05919 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
05920 ** not need to be threadsafe either.  All other methods must be threadsafe
05921 ** in multithreaded applications.
05922 **
05923 ** ^SQLite will never invoke xInit() more than once without an intervening
05924 ** call to xShutdown().
05925 **
05926 ** [[the xCreate() page cache methods]]
05927 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
05928 ** SQLite will typically create one cache instance for each open database file,
05929 ** though this is not guaranteed. ^The
05930 ** first parameter, szPage, is the size in bytes of the pages that must
05931 ** be allocated by the cache.  ^szPage will not be a power of two.  ^szPage
05932 ** will the page size of the database file that is to be cached plus an
05933 ** increment (here called "R") of less than 250.  SQLite will use the
05934 ** extra R bytes on each page to store metadata about the underlying
05935 ** database page on disk.  The value of R depends
05936 ** on the SQLite version, the target platform, and how SQLite was compiled.
05937 ** ^(R is constant for a particular build of SQLite. Except, there are two
05938 ** distinct values of R when SQLite is compiled with the proprietary
05939 ** ZIPVFS extension.)^  ^The second argument to
05940 ** xCreate(), bPurgeable, is true if the cache being created will
05941 ** be used to cache database pages of a file stored on disk, or
05942 ** false if it is used for an in-memory database. The cache implementation
05943 ** does not have to do anything special based with the value of bPurgeable;
05944 ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
05945 ** never invoke xUnpin() except to deliberately delete a page.
05946 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
05947 ** false will always have the "discard" flag set to true.  
05948 ** ^Hence, a cache created with bPurgeable false will
05949 ** never contain any unpinned pages.
05950 **
05951 ** [[the xCachesize() page cache method]]
05952 ** ^(The xCachesize() method may be called at any time by SQLite to set the
05953 ** suggested maximum cache-size (number of pages stored by) the cache
05954 ** instance passed as the first argument. This is the value configured using
05955 ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
05956 ** parameter, the implementation is not required to do anything with this
05957 ** value; it is advisory only.
05958 **
05959 ** [[the xPagecount() page cache methods]]
05960 ** The xPagecount() method must return the number of pages currently
05961 ** stored in the cache, both pinned and unpinned.
05962 ** 
05963 ** [[the xFetch() page cache methods]]
05964 ** The xFetch() method locates a page in the cache and returns a pointer to 
05965 ** the page, or a NULL pointer.
05966 ** A "page", in this context, means a buffer of szPage bytes aligned at an
05967 ** 8-byte boundary. The page to be fetched is determined by the key. ^The
05968 ** minimum key value is 1.  After it has been retrieved using xFetch, the page 
05969 ** is considered to be "pinned".
05970 **
05971 ** If the requested page is already in the page cache, then the page cache
05972 ** implementation must return a pointer to the page buffer with its content
05973 ** intact.  If the requested page is not already in the cache, then the
05974 ** cache implementation should use the value of the createFlag
05975 ** parameter to help it determined what action to take:
05976 **
05977 ** <table border=1 width=85% align=center>
05978 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
05979 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
05980 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
05981 **                 Otherwise return NULL.
05982 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
05983 **                 NULL if allocating a new page is effectively impossible.
05984 ** </table>
05985 **
05986 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
05987 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
05988 ** failed.)^  In between the to xFetch() calls, SQLite may
05989 ** attempt to unpin one or more cache pages by spilling the content of
05990 ** pinned pages to disk and synching the operating system disk cache.
05991 **
05992 ** [[the xUnpin() page cache method]]
05993 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
05994 ** as its second argument.  If the third parameter, discard, is non-zero,
05995 ** then the page must be evicted from the cache.
05996 ** ^If the discard parameter is
05997 ** zero, then the page may be discarded or retained at the discretion of
05998 ** page cache implementation. ^The page cache implementation
05999 ** may choose to evict unpinned pages at any time.
06000 **
06001 ** The cache must not perform any reference counting. A single 
06002 ** call to xUnpin() unpins the page regardless of the number of prior calls 
06003 ** to xFetch().
06004 **
06005 ** [[the xRekey() page cache methods]]
06006 ** The xRekey() method is used to change the key value associated with the
06007 ** page passed as the second argument. If the cache
06008 ** previously contains an entry associated with newKey, it must be
06009 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
06010 ** to be pinned.
06011 **
06012 ** When SQLite calls the xTruncate() method, the cache must discard all
06013 ** existing cache entries with page numbers (keys) greater than or equal
06014 ** to the value of the iLimit parameter passed to xTruncate(). If any
06015 ** of these pages are pinned, they are implicitly unpinned, meaning that
06016 ** they can be safely discarded.
06017 **
06018 ** [[the xDestroy() page cache method]]
06019 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
06020 ** All resources associated with the specified cache should be freed. ^After
06021 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
06022 ** handle invalid, and will not use it with any other sqlite3_pcache_methods
06023 ** functions.
06024 */
06025 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
06026 struct sqlite3_pcache_methods {
06027   void *pArg;
06028   int (*xInit)(void*);
06029   void (*xShutdown)(void*);
06030   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
06031   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
06032   int (*xPagecount)(sqlite3_pcache*);
06033   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
06034   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
06035   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
06036   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
06037   void (*xDestroy)(sqlite3_pcache*);
06038 };
06039 
06040 /*
06041 ** CAPI3REF: Online Backup Object
06042 **
06043 ** The sqlite3_backup object records state information about an ongoing
06044 ** online backup operation.  ^The sqlite3_backup object is created by
06045 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
06046 ** [sqlite3_backup_finish()].
06047 **
06048 ** See Also: [Using the SQLite Online Backup API]
06049 */
06050 typedef struct sqlite3_backup sqlite3_backup;
06051 
06052 /*
06053 ** CAPI3REF: Online Backup API.
06054 **
06055 ** The backup API copies the content of one database into another.
06056 ** It is useful either for creating backups of databases or
06057 ** for copying in-memory databases to or from persistent files. 
06058 **
06059 ** See Also: [Using the SQLite Online Backup API]
06060 **
06061 ** ^SQLite holds a write transaction open on the destination database file
06062 ** for the duration of the backup operation.
06063 ** ^The source database is read-locked only while it is being read;
06064 ** it is not locked continuously for the entire backup operation.
06065 ** ^Thus, the backup may be performed on a live source database without
06066 ** preventing other database connections from
06067 ** reading or writing to the source database while the backup is underway.
06068 ** 
06069 ** ^(To perform a backup operation: 
06070 **   <ol>
06071 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
06072 **         backup, 
06073 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 
06074 **         the data between the two databases, and finally
06075 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources 
06076 **         associated with the backup operation. 
06077 **   </ol>)^
06078 ** There should be exactly one call to sqlite3_backup_finish() for each
06079 ** successful call to sqlite3_backup_init().
06080 **
06081 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
06082 **
06083 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 
06084 ** [database connection] associated with the destination database 
06085 ** and the database name, respectively.
06086 ** ^The database name is "main" for the main database, "temp" for the
06087 ** temporary database, or the name specified after the AS keyword in
06088 ** an [ATTACH] statement for an attached database.
06089 ** ^The S and M arguments passed to 
06090 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
06091 ** and database name of the source database, respectively.
06092 ** ^The source and destination [database connections] (parameters S and D)
06093 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
06094 ** an error.
06095 **
06096 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
06097 ** returned and an error code and error message are stored in the
06098 ** destination [database connection] D.
06099 ** ^The error code and message for the failed call to sqlite3_backup_init()
06100 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
06101 ** [sqlite3_errmsg16()] functions.
06102 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
06103 ** [sqlite3_backup] object.
06104 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
06105 ** sqlite3_backup_finish() functions to perform the specified backup 
06106 ** operation.
06107 **
06108 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
06109 **
06110 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 
06111 ** the source and destination databases specified by [sqlite3_backup] object B.
06112 ** ^If N is negative, all remaining source pages are copied. 
06113 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
06114 ** are still more pages to be copied, then the function returns [SQLITE_OK].
06115 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
06116 ** from source to destination, then it returns [SQLITE_DONE].
06117 ** ^If an error occurs while running sqlite3_backup_step(B,N),
06118 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
06119 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
06120 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
06121 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
06122 **
06123 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
06124 ** <ol>
06125 ** <li> the destination database was opened read-only, or
06126 ** <li> the destination database is using write-ahead-log journaling
06127 ** and the destination and source page sizes differ, or
06128 ** <li> the destination database is an in-memory database and the
06129 ** destination and source page sizes differ.
06130 ** </ol>)^
06131 **
06132 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
06133 ** the [sqlite3_busy_handler | busy-handler function]
06134 ** is invoked (if one is specified). ^If the 
06135 ** busy-handler returns non-zero before the lock is available, then 
06136 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
06137 ** sqlite3_backup_step() can be retried later. ^If the source
06138 ** [database connection]
06139 ** is being used to write to the source database when sqlite3_backup_step()
06140 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
06141 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
06142 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
06143 ** [SQLITE_READONLY] is returned, then 
06144 ** there is no point in retrying the call to sqlite3_backup_step(). These 
06145 ** errors are considered fatal.)^  The application must accept 
06146 ** that the backup operation has failed and pass the backup operation handle 
06147 ** to the sqlite3_backup_finish() to release associated resources.
06148 **
06149 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
06150 ** on the destination file. ^The exclusive lock is not released until either 
06151 ** sqlite3_backup_finish() is called or the backup operation is complete 
06152 ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
06153 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
06154 ** lasts for the duration of the sqlite3_backup_step() call.
06155 ** ^Because the source database is not locked between calls to
06156 ** sqlite3_backup_step(), the source database may be modified mid-way
06157 ** through the backup process.  ^If the source database is modified by an
06158 ** external process or via a database connection other than the one being
06159 ** used by the backup operation, then the backup will be automatically
06160 ** restarted by the next call to sqlite3_backup_step(). ^If the source 
06161 ** database is modified by the using the same database connection as is used
06162 ** by the backup operation, then the backup database is automatically
06163 ** updated at the same time.
06164 **
06165 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
06166 **
06167 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 
06168 ** application wishes to abandon the backup operation, the application
06169 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
06170 ** ^The sqlite3_backup_finish() interfaces releases all
06171 ** resources associated with the [sqlite3_backup] object. 
06172 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
06173 ** active write-transaction on the destination database is rolled back.
06174 ** The [sqlite3_backup] object is invalid
06175 ** and may not be used following a call to sqlite3_backup_finish().
06176 **
06177 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
06178 ** sqlite3_backup_step() errors occurred, regardless or whether or not
06179 ** sqlite3_backup_step() completed.
06180 ** ^If an out-of-memory condition or IO error occurred during any prior
06181 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
06182 ** sqlite3_backup_finish() returns the corresponding [error code].
06183 **
06184 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
06185 ** is not a permanent error and does not affect the return value of
06186 ** sqlite3_backup_finish().
06187 **
06188 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
06189 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
06190 **
06191 ** ^Each call to sqlite3_backup_step() sets two values inside
06192 ** the [sqlite3_backup] object: the number of pages still to be backed
06193 ** up and the total number of pages in the source database file.
06194 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
06195 ** retrieve these two values, respectively.
06196 **
06197 ** ^The values returned by these functions are only updated by
06198 ** sqlite3_backup_step(). ^If the source database is modified during a backup
06199 ** operation, then the values are not updated to account for any extra
06200 ** pages that need to be updated or the size of the source database file
06201 ** changing.
06202 **
06203 ** <b>Concurrent Usage of Database Handles</b>
06204 **
06205 ** ^The source [database connection] may be used by the application for other
06206 ** purposes while a backup operation is underway or being initialized.
06207 ** ^If SQLite is compiled and configured to support threadsafe database
06208 ** connections, then the source database connection may be used concurrently
06209 ** from within other threads.
06210 **
06211 ** However, the application must guarantee that the destination 
06212 ** [database connection] is not passed to any other API (by any thread) after 
06213 ** sqlite3_backup_init() is called and before the corresponding call to
06214 ** sqlite3_backup_finish().  SQLite does not currently check to see
06215 ** if the application incorrectly accesses the destination [database connection]
06216 ** and so no error code is reported, but the operations may malfunction
06217 ** nevertheless.  Use of the destination database connection while a
06218 ** backup is in progress might also also cause a mutex deadlock.
06219 **
06220 ** If running in [shared cache mode], the application must
06221 ** guarantee that the shared cache used by the destination database
06222 ** is not accessed while the backup is running. In practice this means
06223 ** that the application must guarantee that the disk file being 
06224 ** backed up to is not accessed by any connection within the process,
06225 ** not just the specific connection that was passed to sqlite3_backup_init().
06226 **
06227 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 
06228 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
06229 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
06230 ** APIs are not strictly speaking threadsafe. If they are invoked at the
06231 ** same time as another thread is invoking sqlite3_backup_step() it is
06232 ** possible that they return invalid values.
06233 */
06234 SQLITE_API sqlite3_backup *sqlite3_backup_init(
06235   sqlite3 *pDest,                        /* Destination database handle */
06236   const char *zDestName,                 /* Destination database name */
06237   sqlite3 *pSource,                      /* Source database handle */
06238   const char *zSourceName                /* Source database name */
06239 );
06240 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
06241 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
06242 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
06243 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
06244 
06245 /*
06246 ** CAPI3REF: Unlock Notification
06247 **
06248 ** ^When running in shared-cache mode, a database operation may fail with
06249 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
06250 ** individual tables within the shared-cache cannot be obtained. See
06251 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 
06252 ** ^This API may be used to register a callback that SQLite will invoke 
06253 ** when the connection currently holding the required lock relinquishes it.
06254 ** ^This API is only available if the library was compiled with the
06255 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
06256 **
06257 ** See Also: [Using the SQLite Unlock Notification Feature].
06258 **
06259 ** ^Shared-cache locks are released when a database connection concludes
06260 ** its current transaction, either by committing it or rolling it back. 
06261 **
06262 ** ^When a connection (known as the blocked connection) fails to obtain a
06263 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
06264 ** identity of the database connection (the blocking connection) that
06265 ** has locked the required resource is stored internally. ^After an 
06266 ** application receives an SQLITE_LOCKED error, it may call the
06267 ** sqlite3_unlock_notify() method with the blocked connection handle as 
06268 ** the first argument to register for a callback that will be invoked
06269 ** when the blocking connections current transaction is concluded. ^The
06270 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
06271 ** call that concludes the blocking connections transaction.
06272 **
06273 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
06274 ** there is a chance that the blocking connection will have already
06275 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
06276 ** If this happens, then the specified callback is invoked immediately,
06277 ** from within the call to sqlite3_unlock_notify().)^
06278 **
06279 ** ^If the blocked connection is attempting to obtain a write-lock on a
06280 ** shared-cache table, and more than one other connection currently holds
06281 ** a read-lock on the same table, then SQLite arbitrarily selects one of 
06282 ** the other connections to use as the blocking connection.
06283 **
06284 ** ^(There may be at most one unlock-notify callback registered by a 
06285 ** blocked connection. If sqlite3_unlock_notify() is called when the
06286 ** blocked connection already has a registered unlock-notify callback,
06287 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
06288 ** called with a NULL pointer as its second argument, then any existing
06289 ** unlock-notify callback is canceled. ^The blocked connections 
06290 ** unlock-notify callback may also be canceled by closing the blocked
06291 ** connection using [sqlite3_close()].
06292 **
06293 ** The unlock-notify callback is not reentrant. If an application invokes
06294 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
06295 ** crash or deadlock may be the result.
06296 **
06297 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
06298 ** returns SQLITE_OK.
06299 **
06300 ** <b>Callback Invocation Details</b>
06301 **
06302 ** When an unlock-notify callback is registered, the application provides a 
06303 ** single void* pointer that is passed to the callback when it is invoked.
06304 ** However, the signature of the callback function allows SQLite to pass
06305 ** it an array of void* context pointers. The first argument passed to
06306 ** an unlock-notify callback is a pointer to an array of void* pointers,
06307 ** and the second is the number of entries in the array.
06308 **
06309 ** When a blocking connections transaction is concluded, there may be
06310 ** more than one blocked connection that has registered for an unlock-notify
06311 ** callback. ^If two or more such blocked connections have specified the
06312 ** same callback function, then instead of invoking the callback function
06313 ** multiple times, it is invoked once with the set of void* context pointers
06314 ** specified by the blocked connections bundled together into an array.
06315 ** This gives the application an opportunity to prioritize any actions 
06316 ** related to the set of unblocked database connections.
06317 **
06318 ** <b>Deadlock Detection</b>
06319 **
06320 ** Assuming that after registering for an unlock-notify callback a 
06321 ** database waits for the callback to be issued before taking any further
06322 ** action (a reasonable assumption), then using this API may cause the
06323 ** application to deadlock. For example, if connection X is waiting for
06324 ** connection Y's transaction to be concluded, and similarly connection
06325 ** Y is waiting on connection X's transaction, then neither connection
06326 ** will proceed and the system may remain deadlocked indefinitely.
06327 **
06328 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
06329 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
06330 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
06331 ** unlock-notify callback is registered. The system is said to be in
06332 ** a deadlocked state if connection A has registered for an unlock-notify
06333 ** callback on the conclusion of connection B's transaction, and connection
06334 ** B has itself registered for an unlock-notify callback when connection
06335 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
06336 ** the system is also considered to be deadlocked if connection B has
06337 ** registered for an unlock-notify callback on the conclusion of connection
06338 ** C's transaction, where connection C is waiting on connection A. ^Any
06339 ** number of levels of indirection are allowed.
06340 **
06341 ** <b>The "DROP TABLE" Exception</b>
06342 **
06343 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 
06344 ** always appropriate to call sqlite3_unlock_notify(). There is however,
06345 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
06346 ** SQLite checks if there are any currently executing SELECT statements
06347 ** that belong to the same connection. If there are, SQLITE_LOCKED is
06348 ** returned. In this case there is no "blocking connection", so invoking
06349 ** sqlite3_unlock_notify() results in the unlock-notify callback being
06350 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
06351 ** or "DROP INDEX" query, an infinite loop might be the result.
06352 **
06353 ** One way around this problem is to check the extended error code returned
06354 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
06355 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
06356 ** the special "DROP TABLE/INDEX" case, the extended error code is just 
06357 ** SQLITE_LOCKED.)^
06358 */
06359 SQLITE_API int sqlite3_unlock_notify(
06360   sqlite3 *pBlocked,                          /* Waiting connection */
06361   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
06362   void *pNotifyArg                            /* Argument to pass to xNotify */
06363 );
06364 
06365 
06366 /*
06367 ** CAPI3REF: String Comparison
06368 **
06369 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to
06370 ** compare the contents of two buffers containing UTF-8 strings in a
06371 ** case-independent fashion, using the same definition of case independence 
06372 ** that SQLite uses internally when comparing identifiers.
06373 */
06374 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
06375 
06376 /*
06377 ** CAPI3REF: Error Logging Interface
06378 **
06379 ** ^The [sqlite3_log()] interface writes a message into the error log
06380 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
06381 ** ^If logging is enabled, the zFormat string and subsequent arguments are
06382 ** used with [sqlite3_snprintf()] to generate the final output string.
06383 **
06384 ** The sqlite3_log() interface is intended for use by extensions such as
06385 ** virtual tables, collating functions, and SQL functions.  While there is
06386 ** nothing to prevent an application from calling sqlite3_log(), doing so
06387 ** is considered bad form.
06388 **
06389 ** The zFormat string must not be NULL.
06390 **
06391 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
06392 ** will not use dynamically allocated memory.  The log message is stored in
06393 ** a fixed-length buffer on the stack.  If the log message is longer than
06394 ** a few hundred characters, it will be truncated to the length of the
06395 ** buffer.
06396 */
06397 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
06398 
06399 /*
06400 ** CAPI3REF: Write-Ahead Log Commit Hook
06401 **
06402 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
06403 ** will be invoked each time a database connection commits data to a
06404 ** [write-ahead log] (i.e. whenever a transaction is committed in
06405 ** [journal_mode | journal_mode=WAL mode]). 
06406 **
06407 ** ^The callback is invoked by SQLite after the commit has taken place and 
06408 ** the associated write-lock on the database released, so the implementation 
06409 ** may read, write or [checkpoint] the database as required.
06410 **
06411 ** ^The first parameter passed to the callback function when it is invoked
06412 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
06413 ** registering the callback. ^The second is a copy of the database handle.
06414 ** ^The third parameter is the name of the database that was written to -
06415 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
06416 ** is the number of pages currently in the write-ahead log file,
06417 ** including those that were just committed.
06418 **
06419 ** The callback function should normally return [SQLITE_OK].  ^If an error
06420 ** code is returned, that error will propagate back up through the
06421 ** SQLite code base to cause the statement that provoked the callback
06422 ** to report an error, though the commit will have still occurred. If the
06423 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
06424 ** that does not correspond to any valid SQLite error code, the results
06425 ** are undefined.
06426 **
06427 ** A single database handle may have at most a single write-ahead log callback 
06428 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
06429 ** previously registered write-ahead log callback. ^Note that the
06430 ** [sqlite3_wal_autocheckpoint()] interface and the
06431 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
06432 ** those overwrite any prior [sqlite3_wal_hook()] settings.
06433 */
06434 SQLITE_API void *sqlite3_wal_hook(
06435   sqlite3*, 
06436   int(*)(void *,sqlite3*,const char*,int),
06437   void*
06438 );
06439 
06440 /*
06441 ** CAPI3REF: Configure an auto-checkpoint
06442 **
06443 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
06444 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
06445 ** to automatically [checkpoint]
06446 ** after committing a transaction if there are N or
06447 ** more frames in the [write-ahead log] file.  ^Passing zero or 
06448 ** a negative value as the nFrame parameter disables automatic
06449 ** checkpoints entirely.
06450 **
06451 ** ^The callback registered by this function replaces any existing callback
06452 ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
06453 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
06454 ** configured by this function.
06455 **
06456 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
06457 ** from SQL.
06458 **
06459 ** ^Every new [database connection] defaults to having the auto-checkpoint
06460 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
06461 ** pages.  The use of this interface
06462 ** is only necessary if the default setting is found to be suboptimal
06463 ** for a particular application.
06464 */
06465 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
06466 
06467 /*
06468 ** CAPI3REF: Checkpoint a database
06469 **
06470 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
06471 ** on [database connection] D to be [checkpointed].  ^If X is NULL or an
06472 ** empty string, then a checkpoint is run on all databases of
06473 ** connection D.  ^If the database connection D is not in
06474 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
06475 **
06476 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
06477 ** from SQL.  ^The [sqlite3_wal_autocheckpoint()] interface and the
06478 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
06479 ** run whenever the WAL reaches a certain size threshold.
06480 **
06481 ** See also: [sqlite3_wal_checkpoint_v2()]
06482 */
06483 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
06484 
06485 /*
06486 ** CAPI3REF: Checkpoint a database
06487 **
06488 ** Run a checkpoint operation on WAL database zDb attached to database 
06489 ** handle db. The specific operation is determined by the value of the 
06490 ** eMode parameter:
06491 **
06492 ** <dl>
06493 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
06494 **   Checkpoint as many frames as possible without waiting for any database 
06495 **   readers or writers to finish. Sync the db file if all frames in the log
06496 **   are checkpointed. This mode is the same as calling 
06497 **   sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
06498 **
06499 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
06500 **   This mode blocks (calls the busy-handler callback) until there is no
06501 **   database writer and all readers are reading from the most recent database
06502 **   snapshot. It then checkpoints all frames in the log file and syncs the
06503 **   database file. This call blocks database writers while it is running,
06504 **   but not database readers.
06505 **
06506 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
06507 **   This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 
06508 **   checkpointing the log file it blocks (calls the busy-handler callback)
06509 **   until all readers are reading from the database file only. This ensures 
06510 **   that the next client to write to the database file restarts the log file 
06511 **   from the beginning. This call blocks database writers while it is running,
06512 **   but not database readers.
06513 ** </dl>
06514 **
06515 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
06516 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
06517 ** the total number of checkpointed frames (including any that were already
06518 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
06519 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
06520 ** If no values are available because of an error, they are both set to -1
06521 ** before returning to communicate this to the caller.
06522 **
06523 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
06524 ** any other process is running a checkpoint operation at the same time, the 
06525 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 
06526 ** busy-handler configured, it will not be invoked in this case.
06527 **
06528 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 
06529 ** "writer" lock on the database file. If the writer lock cannot be obtained
06530 ** immediately, and a busy-handler is configured, it is invoked and the writer
06531 ** lock retried until either the busy-handler returns 0 or the lock is
06532 ** successfully obtained. The busy-handler is also invoked while waiting for
06533 ** database readers as described above. If the busy-handler returns 0 before
06534 ** the writer lock is obtained or while waiting for database readers, the
06535 ** checkpoint operation proceeds from that point in the same way as 
06536 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 
06537 ** without blocking any further. SQLITE_BUSY is returned in this case.
06538 **
06539 ** If parameter zDb is NULL or points to a zero length string, then the
06540 ** specified operation is attempted on all WAL databases. In this case the
06541 ** values written to output parameters *pnLog and *pnCkpt are undefined. If 
06542 ** an SQLITE_BUSY error is encountered when processing one or more of the 
06543 ** attached WAL databases, the operation is still attempted on any remaining 
06544 ** attached databases and SQLITE_BUSY is returned to the caller. If any other 
06545 ** error occurs while processing an attached database, processing is abandoned 
06546 ** and the error code returned to the caller immediately. If no error 
06547 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 
06548 ** databases, SQLITE_OK is returned.
06549 **
06550 ** If database zDb is the name of an attached database that is not in WAL
06551 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
06552 ** zDb is not NULL (or a zero length string) and is not the name of any
06553 ** attached database, SQLITE_ERROR is returned to the caller.
06554 */
06555 SQLITE_API int sqlite3_wal_checkpoint_v2(
06556   sqlite3 *db,                    /* Database handle */
06557   const char *zDb,                /* Name of attached database (or NULL) */
06558   int eMode,                      /* SQLITE_CHECKPOINT_* value */
06559   int *pnLog,                     /* OUT: Size of WAL log in frames */
06560   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
06561 );
06562 
06563 /*
06564 ** CAPI3REF: Checkpoint operation parameters
06565 **
06566 ** These constants can be used as the 3rd parameter to
06567 ** [sqlite3_wal_checkpoint_v2()].  See the [sqlite3_wal_checkpoint_v2()]
06568 ** documentation for additional information about the meaning and use of
06569 ** each of these values.
06570 */
06571 #define SQLITE_CHECKPOINT_PASSIVE 0
06572 #define SQLITE_CHECKPOINT_FULL    1
06573 #define SQLITE_CHECKPOINT_RESTART 2
06574 
06575 /*
06576 ** CAPI3REF: Virtual Table Interface Configuration
06577 **
06578 ** This function may be called by either the [xConnect] or [xCreate] method
06579 ** of a [virtual table] implementation to configure
06580 ** various facets of the virtual table interface.
06581 **
06582 ** If this interface is invoked outside the context of an xConnect or
06583 ** xCreate virtual table method then the behavior is undefined.
06584 **
06585 ** At present, there is only one option that may be configured using
06586 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
06587 ** may be added in the future.
06588 */
06589 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
06590 
06591 /*
06592 ** CAPI3REF: Virtual Table Configuration Options
06593 **
06594 ** These macros define the various options to the
06595 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
06596 ** can use to customize and optimize their behavior.
06597 **
06598 ** <dl>
06599 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
06600 ** <dd>Calls of the form
06601 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
06602 ** where X is an integer.  If X is zero, then the [virtual table] whose
06603 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
06604 ** support constraints.  In this configuration (which is the default) if
06605 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
06606 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
06607 ** specified as part of the users SQL statement, regardless of the actual
06608 ** ON CONFLICT mode specified.
06609 **
06610 ** If X is non-zero, then the virtual table implementation guarantees
06611 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
06612 ** any modifications to internal or persistent data structures have been made.
06613 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 
06614 ** is able to roll back a statement or database transaction, and abandon
06615 ** or continue processing the current SQL statement as appropriate. 
06616 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
06617 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
06618 ** had been ABORT.
06619 **
06620 ** Virtual table implementations that are required to handle OR REPLACE
06621 ** must do so within the [xUpdate] method. If a call to the 
06622 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 
06623 ** CONFLICT policy is REPLACE, the virtual table implementation should 
06624 ** silently replace the appropriate rows within the xUpdate callback and
06625 ** return SQLITE_OK. Or, if this is not possible, it may return
06626 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 
06627 ** constraint handling.
06628 ** </dl>
06629 */
06630 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
06631 
06632 /*
06633 ** CAPI3REF: Determine The Virtual Table Conflict Policy
06634 **
06635 ** This function may only be called from within a call to the [xUpdate] method
06636 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
06637 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
06638 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
06639 ** of the SQL statement that triggered the call to the [xUpdate] method of the
06640 ** [virtual table].
06641 */
06642 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
06643 
06644 /*
06645 ** CAPI3REF: Conflict resolution modes
06646 **
06647 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
06648 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
06649 ** is for the SQL statement being evaluated.
06650 **
06651 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
06652 ** return value from the [sqlite3_set_authorizer()] callback and that
06653 ** [SQLITE_ABORT] is also a [result code].
06654 */
06655 #define SQLITE_ROLLBACK 1
06656 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
06657 #define SQLITE_FAIL     3
06658 /* #define SQLITE_ABORT 4  // Also an error code */
06659 #define SQLITE_REPLACE  5
06660 
06661 
06662 
06663 /*
06664 ** Undo the hack that converts floating point types to integer for
06665 ** builds on processors without floating point support.
06666 */
06667 #ifdef SQLITE_OMIT_FLOATING_POINT
06668 # undef double
06669 #endif
06670 
06671 #ifdef __cplusplus
06672 }  /* End of the 'extern "C"' block */
06673 #endif
06674 #endif
06675 
06676 /*
06677 ** 2010 August 30
06678 **
06679 ** The author disclaims copyright to this source code.  In place of
06680 ** a legal notice, here is a blessing:
06681 **
06682 **    May you do good and not evil.
06683 **    May you find forgiveness for yourself and forgive others.
06684 **    May you share freely, never taking more than you give.
06685 **
06686 *************************************************************************
06687 */
06688 
06689 #ifndef _SQLITE3RTREE_H_
06690 #define _SQLITE3RTREE_H_
06691 
06692 
06693 #ifdef __cplusplus
06694 extern "C" {
06695 #endif
06696 
06697 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
06698 
06699 /*
06700 ** Register a geometry callback named zGeom that can be used as part of an
06701 ** R-Tree geometry query as follows:
06702 **
06703 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
06704 */
06705 SQLITE_API int sqlite3_rtree_geometry_callback(
06706   sqlite3 *db,
06707   const char *zGeom,
06708   int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes),
06709   void *pContext
06710 );
06711 
06712 
06713 /*
06714 ** A pointer to a structure of the following type is passed as the first
06715 ** argument to callbacks registered using rtree_geometry_callback().
06716 */
06717 struct sqlite3_rtree_geometry {
06718   void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
06719   int nParam;                     /* Size of array aParam[] */
06720   double *aParam;                 /* Parameters passed to SQL geom function */
06721   void *pUser;                    /* Callback implementation user data */
06722   void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
06723 };
06724 
06725 
06726 #ifdef __cplusplus
06727 }  /* end of the 'extern "C"' block */
06728 #endif
06729 
06730 #endif  /* ifndef _SQLITE3RTREE_H_ */
06731