glibc/debug/fgetws_chk.c

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/* Copyright (C) 1993-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include "libioP.h"
#include <wchar.h>
#include <sys/param.h>
wchar_t *
__fgetws_chk (wchar_t *buf, size_t size, int n, _IO_FILE *fp)
{
_IO_size_t count;
wchar_t *result;
int old_error;
CHECK_FILE (fp, NULL);
if (n <= 0)
return NULL;
_IO_acquire_lock (fp);
/* This is very tricky since a file descriptor may be in the
non-blocking mode. The error flag doesn't mean much in this
case. We return an error only when there is a new error. */
old_error = fp->_IO_file_flags & _IO_ERR_SEEN;
fp->_IO_file_flags &= ~_IO_ERR_SEEN;
count = _IO_getwline (fp, buf, MIN ((size_t) n - 1, size), L'\n', 1);
/* If we read in some bytes and errno is EAGAIN, that error will
be reported for next read. */
if (count == 0 || (_IO_ferror_unlocked (fp) && errno != EAGAIN))
result = NULL;
else if (count >= size)
__chk_fail ();
else
{
buf[count] = '\0';
result = buf;
}
fp->_IO_file_flags |= old_error;
_IO_release_lock (fp);
return result;
}