streams/isastream.c

   1 /* Copyright (C) 1998-2017 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <fcntl.h>
  20 #include <stropts.h>
  21
  22 int
  23 isastream (int fildes)
  24 {
  25   /* In general we do not have a STREAMS implementation and therefore
  26      return 0.  But for invalid file descriptors we have to return an
  27      error.  */
  28   if (__fcntl (fildes, F_GETFD) < 0)
  29     return -1;
  30
  31   /* No STREAM.  */
  32   return 0;
  33 }