stdio/fflush.c

   1 /* Copyright (C) 1991, 1996 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <errno.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22
  23 /* Flush STREAM's buffer.
  24    If STREAM is NULL, flush the buffers of all streams that are writing.  */
  25 int
  26 fflush (stream)
  27      register FILE *stream;
  28 {
  29   if (stream == NULL)
  30     {
  31       int lossage = 0;
  32       for (stream = __stdio_head; stream != NULL; stream = stream->__next)
  33         if (__validfp (stream) && stream->__mode.__write)
  34           lossage |= fflush (stream) == EOF;
  35       return lossage ? EOF : 0;
  36     }
  37
  38   if (!__validfp (stream) || !stream->__mode.__write)
  39     {
  40       __set_errno (EINVAL);
  41       return EOF;
  42     }
  43
  44   return __flshfp (stream, EOF);
  45 }