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glibc  2.9
fgetws_chk.c
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00001 /* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2001, 2005
00002    Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include "libioP.h"
00021 #include <wchar.h>
00022 #include <sys/param.h>
00023 
00024 wchar_t *
00025 __fgetws_chk (wchar_t *buf, size_t size, int n, _IO_FILE *fp)
00026 {
00027   _IO_size_t count;
00028   wchar_t *result;
00029   int old_error;
00030   CHECK_FILE (fp, NULL);
00031   if (n <= 0)
00032     return NULL;
00033   _IO_acquire_lock (fp);
00034   /* This is very tricky since a file descriptor may be in the
00035      non-blocking mode. The error flag doesn't mean much in this
00036      case. We return an error only when there is a new error. */
00037   old_error = fp->_IO_file_flags & _IO_ERR_SEEN;
00038   fp->_IO_file_flags &= ~_IO_ERR_SEEN;
00039   count = _IO_getwline (fp, buf, MIN ((size_t) n - 1, size), L'\n', 1);
00040   /* If we read in some bytes and errno is EAGAIN, that error will
00041      be reported for next read. */
00042   if (count == 0 || (_IO_ferror_unlocked (fp) && errno != EAGAIN))
00043     result = NULL;
00044   else if (count >= size)
00045     __chk_fail ();
00046   else
00047     {
00048       buf[count] = '\0';
00049       result = buf;
00050     }
00051   fp->_IO_file_flags |= old_error;
00052   _IO_release_lock (fp);
00053   return result;
00054 }