1/* Multithreading primitives.
2   Copyright (C) 2005-2010 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 Lesser General Public License as published by
6   the Free Software Foundation; either version 2, 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 Lesser General Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public License
15   along with this program; if not, write to the Free Software Foundation,
16   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
17
18/* Written by Bruno Haible <bruno@clisp.org>, 2005.  */
19
20#include <config.h>
21
22/* ========================================================================= */
23
24#if USE_POSIX_THREADS
25
26/* Use the POSIX threads library.  */
27
28# include <pthread.h>
29# include <stdlib.h>
30
31# if PTHREAD_IN_USE_DETECTION_HARD
32
33/* The function to be executed by a dummy thread.  */
34static void *
35dummy_thread_func (void *arg)
36{
37  return arg;
38}
39
40int
41glthread_in_use (void)
42{
43  static int tested;
44  static int result; /* 1: linked with -lpthread, 0: only with libc */
45
46  if (!tested)
47    {
48      pthread_t thread;
49
50      if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0)
51        /* Thread creation failed.  */
52        result = 0;
53      else
54        {
55          /* Thread creation works.  */
56          void *retval;
57          if (pthread_join (thread, &retval) != 0)
58            abort ();
59          result = 1;
60        }
61      tested = 1;
62    }
63  return result;
64}
65
66# endif
67
68#endif
69
70/* ========================================================================= */
71
72/* This declaration is solely to ensure that after preprocessing
73   this file is never empty.  */
74typedef int dummy;
75