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
22int
23isastream (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}
34