73 lines
1.3 KiB
C
73 lines
1.3 KiB
C
/* $NetBSD: cond3.c,v 1.1 2003/01/30 18:53:47 thorpej Exp $ */
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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 = PTHREAD_MUTEX_INITIALIZER;
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pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
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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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int sharedval;
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printf("1: condition variable test 3\n");
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x = 20;
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pthread_mutex_lock(&mutex);
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sharedval = 1;
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ret = pthread_create(&new, NULL, threadfunc, &sharedval);
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if (ret != 0)
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err(1, "pthread_create");
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printf("1: Before waiting.\n");
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do {
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sleep(2);
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pthread_cond_wait(&cond, &mutex);
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printf("1: After waiting, in loop.\n");
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} while (sharedval != 0);
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printf("1: After the loop.\n");
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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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printf("1: Thread joined.\n");
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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 *share = (int *) arg;
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printf("2: Second thread.\n");
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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.\n");
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printf("Shared value: %d. Changing to 0.\n", *share);
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*share = 0;
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/* Signal first, then unlock, for a different test than #1. */
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pthread_cond_signal(&cond);
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pthread_mutex_unlock(&mutex);
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return NULL;
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}
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