/* 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, FILE *fp)

{

  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->_flags & _IO_ERR_SEEN;

  fp->_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->_flags |= old_error;

  _IO_release_lock (fp);

  return result;

}