1 /* Test mutexes.
2    Copyright (C) 2000-2022 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9 
10    The GNU C Library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14 
15    You should have received a copy of the GNU Lesser General Public
16    License along with the GNU C Library;  if not, see
17    <https://www.gnu.org/licenses/>.  */
18 
19 #define _GNU_SOURCE
20 
21 #include <pthread.h>
22 #include <assert.h>
23 #include <unistd.h>
24 #include <error.h>
25 #include <errno.h>
26 #include <stdio.h>
27 
28 #define THREADS 500
29 
30 void *
foo(void * arg)31 foo (void *arg)
32 {
33   pthread_mutex_t *mutex = arg;
34   pthread_mutex_lock (mutex);
35   pthread_mutex_unlock (mutex);
36   return mutex;
37 }
38 
39 int
main(int argc,char ** argv)40 main (int argc, char **argv)
41 {
42   int i;
43   error_t err;
44   pthread_t tid[THREADS];
45   pthread_mutex_t mutex[THREADS];
46 
47   for (i = 0; i < THREADS; i++)
48     {
49       pthread_mutex_init (&mutex[i], 0);
50       pthread_mutex_lock (&mutex[i]);
51       err = pthread_create (&tid[i], 0, foo, &mutex[i]);
52       if (err)
53 	error (1, err, "pthread_create");
54       sched_yield ();
55     }
56 
57   for (i = THREADS - 1; i >= 0; i--)
58     {
59       void *ret;
60       pthread_mutex_unlock (&mutex[i]);
61       err = pthread_join (tid[i], &ret);
62       if (err)
63 	error (1, err, "pthread_join");
64       assert (ret == &mutex[i]);
65     }
66 
67   return 0;
68 }
69