1/* Copyright (C) 2002-2024 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library 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 GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <pthread.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <unistd.h>
22#include <sys/file.h>
23
24#include <support/xunistd.h>
25
26static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
27
28static int fd;
29
30
31static void *
32tf (void *arg)
33{
34 if (flock (fd: fd, LOCK_SH | LOCK_NB) != 0)
35 {
36 puts (s: "second flock failed");
37 exit (1);
38 }
39
40 pthread_mutex_unlock (mutex: &lock);
41
42 return NULL;
43}
44
45
46static int
47do_test (void)
48{
49 char tmp[] = "/tmp/tst-flock1-XXXXXX";
50
51 fd = mkstemp (template: tmp);
52 if (fd == -1)
53 {
54 puts (s: "mkstemp failed");
55 exit (1);
56 }
57
58 unlink (name: tmp);
59
60 xwrite (fd, "foobar xyzzy", 12);
61
62 if (flock (fd: fd, LOCK_EX | LOCK_NB) != 0)
63 {
64 puts (s: "first flock failed");
65 exit (1);
66 }
67
68 pthread_mutex_lock (mutex: &lock);
69
70 pthread_t th;
71 if (pthread_create (newthread: &th, NULL, start_routine: tf, NULL) != 0)
72 {
73 puts (s: "pthread_create failed");
74 exit (1);
75 }
76
77 pthread_mutex_lock (mutex: &lock);
78
79 void *result;
80 if (pthread_join (th: th, thread_return: &result) != 0)
81 {
82 puts (s: "pthread_join failed");
83 exit (1);
84 }
85
86 close (fd: fd);
87
88 return result != NULL;
89}
90
91#define TEST_FUNCTION do_test ()
92#include "../test-skeleton.c"
93

source code of glibc/sysdeps/pthread/tst-flock1.c