test_sem_post.c revision 83b47ccbc4066ef19f5d95261d8a892567a7f0a7 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29/* This program is used to test that sem_post() will wake up all
30 * threads that are waiting on a single semaphore, and not all of
31 * them.
32 */
33
34#include <pthread.h>
35#include <semaphore.h>
36#include <stdio.h>
37#include <errno.h>
38#include <string.h>
39#include <unistd.h>
40
41static sem_t  semaphore;
42
43/* Thread function, just wait for the semaphore */
44static void*
45thread_func(void* arg)
46{
47    sem_t *psem = (sem_t *)arg;
48    void *me = (void *)pthread_self();
49    printf("thread %p waiting\n", me);
50    sem_wait(psem);
51    printf("thread %p exiting\n", me);
52    return me;
53}
54
55#define MAX_THREADS  50
56
57int main(void)
58{
59    pthread_t   t[MAX_THREADS];
60    int         nn, value;
61
62    /* Initialize to 1, first thread will exit immediately.
63     * this is used to exercize more of the semaphore code path */
64    if ( sem_init( &semaphore, 0, 1 ) < 0 ) {
65        printf( "Could not initialize semaphore: %s\n", strerror(errno) );
66        return 1;
67    }
68
69    for ( nn = 0; nn < MAX_THREADS; nn++ ) {
70        if ( pthread_create( &t[nn], NULL, thread_func, &semaphore ) < 0 ) {
71            printf("Could not create thread %d: %s\n", nn+1, strerror(errno) );
72            return 2;
73        }
74    }
75    sleep( 1 );
76
77    for (nn = 0; nn < MAX_THREADS; nn++) {
78        sem_post(&semaphore);
79    }
80
81    for ( nn = 0; nn < MAX_THREADS; nn++) {
82        void* result;
83        pthread_join(t[nn], &result);
84        if (result != (void*)t[nn]) {
85            printf("Thread %p joined but returned %p\n", (void*)t[nn], result);
86        }
87    }
88
89    if (sem_getvalue(&semaphore, &value) < 0) {
90        printf("Could not get semaphore value: %s\n", strerror(errno));
91        return 3;
92    }
93    if (value != 1) {
94        printf("Error: Semaphore value = %d\n", value);
95        return 4;
96    }
97    return 0;
98}
99