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glibc  2.9
iogets.c
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00001 /* Copyright (C) 1993,1996,1997,1998,2002,2003 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.
00018 
00019    As a special exception, if you link the code in this file with
00020    files compiled with a GNU compiler to produce an executable,
00021    that does not cause the resulting executable to be covered by
00022    the GNU Lesser General Public License.  This exception does not
00023    however invalidate any other reasons why the executable file
00024    might be covered by the GNU Lesser General Public License.
00025    This exception applies to code released by its copyright holders
00026    in files containing the exception.  */
00027 
00028 #include "libioP.h"
00029 #include <limits.h>
00030 
00031 char*
00032 _IO_gets (buf)
00033      char *buf;
00034 {
00035   _IO_size_t count;
00036   int ch;
00037   char *retval;
00038 
00039   _IO_acquire_lock (_IO_stdin);
00040   ch = _IO_getc_unlocked (_IO_stdin);
00041   if (ch == EOF)
00042     {
00043       retval = NULL;
00044       goto unlock_return;
00045     }
00046   if (ch == '\n')
00047     count = 0;
00048   else
00049     {
00050       /* This is very tricky since a file descriptor may be in the
00051         non-blocking mode. The error flag doesn't mean much in this
00052         case. We return an error only when there is a new error. */
00053       int old_error = _IO_stdin->_IO_file_flags & _IO_ERR_SEEN;
00054       _IO_stdin->_IO_file_flags &= ~_IO_ERR_SEEN;
00055       buf[0] = (char) ch;
00056       count = INTUSE(_IO_getline) (_IO_stdin, buf + 1, INT_MAX, '\n', 0) + 1;
00057       if (_IO_stdin->_IO_file_flags & _IO_ERR_SEEN)
00058        {
00059          retval = NULL;
00060          goto unlock_return;
00061        }
00062       else
00063        _IO_stdin->_IO_file_flags |= old_error;
00064     }
00065   buf[count] = 0;
00066   retval = buf;
00067 unlock_return:
00068   _IO_release_lock (_IO_stdin);
00069   return retval;
00070 }
00071 
00072 #ifdef weak_alias
00073 weak_alias (_IO_gets, gets)
00074 #endif
00075 
00076 #ifdef _LIBC
00077 link_warning (gets, "the `gets' function is dangerous and should not be used.")
00078 #endif