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1 /*
2  * Copyright (C) 2008 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 #include <pthread.h>
29 #include <semaphore.h>
30 #include <errno.h>
31 #include <stdio.h>
32 #include <time.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 static pthread_mutex_t lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER;
37 static pthread_cond_t  wait = PTHREAD_COND_INITIALIZER;
38 
_thread1(void * __u)39 static void* _thread1(void *__u __attribute__((unused)))
40 {
41     printf("1: obtaining mutex\n");
42     pthread_mutex_lock(&lock);
43     printf("1: waiting on condition variable\n");
44     pthread_cond_wait(&wait, &lock);
45     printf("1: releasing mutex\n");
46     pthread_mutex_unlock(&lock);
47     printf("1: exiting\n");
48     return NULL;
49 }
50 
_thread2(void * __u)51 static void* _thread2(void *__u __attribute__((unused)))
52 {
53     int cnt = 2;
54     while(cnt--) {
55         printf("2: obtaining mutex\n");
56         pthread_mutex_lock(&lock);
57         printf("2: signaling\n");
58         pthread_cond_signal(&wait);
59         printf("2: releasing mutex\n");
60         pthread_mutex_unlock(&lock);
61     }
62 
63     printf("2: exiting\n");
64     return NULL;
65 }
66 
67 typedef void* (*thread_func)(void*);
68 static const  thread_func thread_routines[] =
69 {
70     &_thread1,
71     &_thread2,
72 };
73 
main(void)74 int main(void)
75 {
76     pthread_t t[2];
77     int nn;
78     int count = (int)(sizeof t/sizeof t[0]);
79 
80     for (nn = 0; nn < count; nn++) {
81         printf("main: creating thread %d\n", nn+1);
82         if (pthread_create( &t[nn], NULL, thread_routines[nn], NULL) < 0) {
83             printf("main: could not create thread %d: %s\n", nn+1, strerror(errno));
84             return -2;
85         }
86     }
87 
88     for (nn = 0; nn < count; nn++) {
89         printf("main: joining thread %d\n", nn+1);
90         if (pthread_join(t[nn], NULL)) {
91             printf("main: could not join thread %d: %s\n", nn+1, strerror(errno));
92             return -2;
93         }
94     }
95 
96     return 0;
97 }
98