1 /* Multithreading primitives.
2 Copyright (C) 2005-2012 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. */
33 static void *
dummy_thread_func(void * arg)34 dummy_thread_func (void *arg)
35 {
36 return arg;
37 }
38
39 int
glthread_in_use(void)40 glthread_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. */
73 typedef int dummy;
74