84 lines
1.9 KiB
C
84 lines
1.9 KiB
C
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#include <stdio.h>
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#include <pthread.h>
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#include <unistd.h>
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// 条件变量实例
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// 互斥锁和条件变量的初始化
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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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void *producer_task(void *data)
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{
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int *n = (int *)data;
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while (1)
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{
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pthread_mutex_lock(&mutex);
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while (*n == 10) // 只要资源为 10 ，就等待
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{
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// 条件变量等待后，会自动释放 mutex 锁
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pthread_cond_wait(&cond, &mutex);
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}
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(*n)++;
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printf("生产线程(%ld)生产了 %d 个产品\n", pthread_self(), *n);
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// 发出通知，让等待消费的线程恢复（条件满足）
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pthread_cond_broadcast(&cond);
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pthread_mutex_unlock(&mutex);
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// usleep(200 * 1000);
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sleep(1);
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}
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pthread_exit(NULL);
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}
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void *consumer_task(void *data)
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{
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int *n = (int *)data;
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while (1)
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{
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pthread_mutex_lock(&mutex);
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while (*n == 0) // 只要资源为 0 ，就等待
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{
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// 条件变量等待后，会自动释放 mutex 锁
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pthread_cond_wait(&cond, &mutex);
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}
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printf("消费者(%ld) 消费了 %d 产品\n", pthread_self(), *n);
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(*n)--;
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pthread_mutex_unlock(&mutex);
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// usleep(200 * 1000);
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sleep(1);
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}
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pthread_exit(NULL);
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}
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int main(int argc, char const *argv[])
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{
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int num = 3; // 3 个产品
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pthread_t threads[10];
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// 创建 2 个生产线程
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for (int i = 0; i < 8; i++)
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{
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pthread_create(&threads[i], NULL, producer_task, &num);
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}
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// 创建 3 个消费者线程
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for (int i = 8; i < 10; i++)
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{
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pthread_create(&threads[i], NULL, consumer_task, &num);
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}
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for (int i = 0; i < 10; i++)
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{
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pthread_join(threads[i], NULL);
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}
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pthread_mutex_destroy(&mutex);
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pthread_cond_destroy(&cond);
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return 0;
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}
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