1/* C11 threads trylock mutex tests.
2 Copyright (C) 2018-2024 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#include <threads.h>
20#include <stdio.h>
21#include <unistd.h>
22
23#include <support/check.h>
24
25/* Shared mutex between child and parent. */
26static mtx_t mutex;
27
28/* Shared counter to check possible race conditions. */
29static char shrd_counter;
30
31/* Function to choose an action to do, depending on mtx_trylock
32 return value. */
33static inline void
34choose_action (int action, char* thread_name)
35{
36 switch (action)
37 {
38 case thrd_success:
39 ++shrd_counter;
40
41 if (mtx_unlock (mutex: &mutex) != thrd_success)
42 FAIL_EXIT1 ("mtx_unlock failed");
43 break;
44
45 case thrd_busy:
46 break;
47
48 case thrd_error:
49 FAIL_EXIT1 ("%s lock error", thread_name);
50 break;
51 }
52}
53
54static int
55child_add (void *arg)
56{
57 char child_name[] = "child";
58
59 /* Try to lock mutex. */
60 choose_action (action: mtx_trylock (mutex: &mutex), thread_name: child_name);
61
62 thrd_exit (res: thrd_success);
63}
64
65static int
66do_test (void)
67{
68 thrd_t id;
69 char parent_name[] = "parent";
70
71 if (mtx_init (mutex: &mutex, type: mtx_timed) != thrd_success)
72 FAIL_EXIT1 ("mtx_init failed");
73
74 if (thrd_create (thr: &id, func: child_add, NULL) != thrd_success)
75 FAIL_EXIT1 ("thrd_create failed");
76
77 choose_action (action: mtx_trylock (mutex: &mutex), thread_name: parent_name);
78
79 if (thrd_join (thr: id, NULL) != thrd_success)
80 FAIL_EXIT1 ("thrd_join failed");
81
82 if (shrd_counter != 2 && shrd_counter != 1)
83 FAIL_EXIT1 ("shrd_counter != {1,2} (%d)", shrd_counter);
84
85 mtx_destroy (mutex: &mutex);
86
87 return 0;
88}
89
90#include <support/test-driver.c>
91

source code of glibc/sysdeps/pthread/tst-mtx-trylock.c