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php5  5.3.10
pcre_version.c
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00001 /*************************************************
00002 *      Perl-Compatible Regular Expressions       *
00003 *************************************************/
00004 
00005 /* PCRE is a library of functions to support regular expressions whose syntax
00006 and semantics are as close as possible to those of the Perl 5 language.
00007 
00008                        Written by Philip Hazel
00009            Copyright (c) 1997-2008 University of Cambridge
00010 
00011 -----------------------------------------------------------------------------
00012 Redistribution and use in source and binary forms, with or without
00013 modification, are permitted provided that the following conditions are met:
00014 
00015     * Redistributions of source code must retain the above copyright notice,
00016       this list of conditions and the following disclaimer.
00017 
00018     * Redistributions in binary form must reproduce the above copyright
00019       notice, this list of conditions and the following disclaimer in the
00020       documentation and/or other materials provided with the distribution.
00021 
00022     * Neither the name of the University of Cambridge nor the names of its
00023       contributors may be used to endorse or promote products derived from
00024       this software without specific prior written permission.
00025 
00026 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00027 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00028 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00029 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
00030 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00031 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
00032 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00033 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00034 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
00035 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00036 POSSIBILITY OF SUCH DAMAGE.
00037 -----------------------------------------------------------------------------
00038 */
00039 
00040 
00041 /* This module contains the external function pcre_version(), which returns a
00042 string that identifies the PCRE version that is in use. */
00043 
00044 
00045 #include "config.h"
00046 
00047 #include "pcre_internal.h"
00048 
00049 
00050 /*************************************************
00051 *          Return version string                 *
00052 *************************************************/
00053 
00054 /* These macros are the standard way of turning unquoted text into C strings.
00055 They allow macros like PCRE_MAJOR to be defined without quotes, which is
00056 convenient for user programs that want to test its value. */
00057 
00058 #define STRING(a)  # a
00059 #define XSTRING(s) STRING(s)
00060 
00061 /* A problem turned up with PCRE_PRERELEASE, which is defined empty for
00062 production releases. Originally, it was used naively in this code:
00063 
00064   return XSTRING(PCRE_MAJOR)
00065          "." XSTRING(PCRE_MINOR)
00066              XSTRING(PCRE_PRERELEASE)
00067          " " XSTRING(PCRE_DATE);
00068 
00069 However, when PCRE_PRERELEASE is empty, this leads to an attempted expansion of
00070 STRING(). The C standard states: "If (before argument substitution) any
00071 argument consists of no preprocessing tokens, the behavior is undefined." It
00072 turns out the gcc treats this case as a single empty string - which is what we
00073 really want - but Visual C grumbles about the lack of an argument for the
00074 macro. Unfortunately, both are within their rights. To cope with both ways of
00075 handling this, I had resort to some messy hackery that does a test at run time.
00076 I could find no way of detecting that a macro is defined as an empty string at
00077 pre-processor time. This hack uses a standard trick for avoiding calling
00078 the STRING macro with an empty argument when doing the test. */
00079 
00080 PCRE_EXP_DEFN const char * PCRE_CALL_CONVENTION
00081 pcre_version(void)
00082 {
00083 return (XSTRING(Z PCRE_PRERELEASE)[1] == 0)?
00084   XSTRING(PCRE_MAJOR.PCRE_MINOR PCRE_DATE) :
00085   XSTRING(PCRE_MAJOR.PCRE_MINOR) XSTRING(PCRE_PRERELEASE PCRE_DATE);
00086 }
00087 
00088 /* End of pcre_version.c */