67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
/* $NetBSD: mutex1.c,v 1.1 2003/01/30 18:05:26 thorpej Exp $ */
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#include <assert.h>
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#include <err.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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void *threadfunc(void *arg);
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pthread_mutex_t mutex;
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int
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main(int argc, char *argv[])
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{
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int x,ret;
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pthread_t new;
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void *joinval;
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printf("1: Mutex-test 1\n");
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pthread_mutex_init(&mutex, NULL);
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x = 1;
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pthread_mutex_lock(&mutex);
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ret = pthread_create(&new, NULL, threadfunc, &x);
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if (ret != 0)
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err(1, "pthread_create");
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printf("1: Before changing the value.\n");
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sleep(2);
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x = 20;
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printf("1: Before releasing the mutex.\n");
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sleep(2);
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pthread_mutex_unlock(&mutex);
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printf("1: After releasing the mutex.\n");
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ret = pthread_join(new, &joinval);
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if (ret != 0)
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err(1, "pthread_join");
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pthread_mutex_lock(&mutex);
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printf("1: Thread joined. X was %d. Return value (int) was %d\n",
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x, *(int *)joinval);
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assert(x == 21);
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assert(*(int *)joinval == 21);
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pthread_mutex_unlock(&mutex);
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return 0;
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}
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void *
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threadfunc(void *arg)
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{
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int *param;
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printf("2: Second thread.\n");
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param = arg;
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printf("2: Locking mutex\n");
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pthread_mutex_lock(&mutex);
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printf("2: Got mutex. *param = %d\n", *param);
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assert(*param == 20);
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(*param)++;
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pthread_mutex_unlock(&mutex);
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return param;
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}
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