streams/isastream.c

   1 /* Copyright (C) 1998 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stropts.h>
  22
  23 int
  24 isastream (fildes)
  25      int fildes;
  26 {
  27   /* In general we do not have a STREAMS implementation and therefore
  28      return 0.  But for invalid file descriptors we have to return an
  29      error.  */
  30   if (__fcntl (fildes, F_GETFD) < 0)
  31     return -1;
  32
  33   /* No STREAM.  */
  34   return 0;
  35 }