debug/fgetws_chk.c

   1 /* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2001, 2005
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include "libioP.h"
  20 #include <wchar.h>
  21 #include <sys/param.h>
  22
  23 wchar_t *
  24 __fgetws_chk (wchar_t *buf, size_t size, int n, _IO_FILE *fp)
  25 {
  26   _IO_size_t count;
  27   wchar_t *result;
  28   int old_error;
  29   CHECK_FILE (fp, NULL);
  30   if (n <= 0)
  31     return NULL;
  32   _IO_acquire_lock (fp);
  33   /* This is very tricky since a file descriptor may be in the
  34      non-blocking mode. The error flag doesn't mean much in this
  35      case. We return an error only when there is a new error. */
  36   old_error = fp->_IO_file_flags & _IO_ERR_SEEN;
  37   fp->_IO_file_flags &= ~_IO_ERR_SEEN;
  38   count = _IO_getwline (fp, buf, MIN ((size_t) n - 1, size), L'\n', 1);
  39   /* If we read in some bytes and errno is EAGAIN, that error will
  40      be reported for next read. */
  41   if (count == 0 || (_IO_ferror_unlocked (fp) && errno != EAGAIN))
  42     result = NULL;
  43   else if (count >= size)
  44     __chk_fail ();
  45   else
  46     {
  47       buf[count] = '\0';
  48       result = buf;
  49     }
  50   fp->_IO_file_flags |= old_error;
  51   _IO_release_lock (fp);
  52   return result;
  53 }