1/* Multithreading primitives.
2   Copyright (C) 2005-2014 Free Software Foundation, Inc.
3
4   This program is free software; you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 3, or (at your option)
7   any later version.
8
9   This program 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
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
16
17/* Written by Bruno Haible <bruno@clisp.org>, 2005.  */
18
19#include <config.h>
20
21/* ========================================================================= */
22
23#if USE_POSIX_THREADS
24
25/* Use the POSIX threads library.  */
26
27# include <pthread.h>
28# include <stdlib.h>
29
30# if PTHREAD_IN_USE_DETECTION_HARD
31
32/* The function to be executed by a dummy thread.  */
33static void *
34dummy_thread_func (void *arg)
35{
36  return arg;
37}
38
39int
40glthread_in_use (void)
41{
42  static int tested;
43  static int result; /* 1: linked with -lpthread, 0: only with libc */
44
45  if (!tested)
46    {
47      pthread_t thread;
48
49      if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0)
50        /* Thread creation failed.  */
51        result = 0;
52      else
53        {
54          /* Thread creation works.  */
55          void *retval;
56          if (pthread_join (thread, &retval) != 0)
57            abort ();
58          result = 1;
59        }
60      tested = 1;
61    }
62  return result;
63}
64
65# endif
66
67#endif
68
69/* ========================================================================= */
70
71/* This declaration is solely to ensure that after preprocessing
72   this file is never empty.  */
73typedef int dummy;
74