生产者消费者问题C语言代码

以下是一个简单的生产者消费者问题的C语言代码：

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

#define BUFFER_SIZE 10

int buffer[BUFFER_SIZE];
int count = 0;

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t full = PTHREAD_COND_INITIALIZER;
pthread_cond_t empty = PTHREAD_COND_INITIALIZER;

void *producer(void *arg)
{
    int item, i;

    for (i = 0; i < 20; i++) {
        item = rand() % 100;
        pthread_mutex_lock(&mutex);
        if (count == BUFFER_SIZE) {
            pthread_cond_wait(&empty, &mutex);
        }

        buffer[count] = item;
        printf("Producer produced %d\n", item);
        count++;

        pthread_mutex_unlock(&mutex);
        pthread_cond_signal(&full);
    }

    pthread_exit(NULL);
}

void *consumer(void *arg)
{
    int item, i;

    for (i = 0; i < 20; i++) {
        pthread_mutex_lock(&mutex);
        if (count == 0) {
            pthread_cond_wait(&full, &mutex);
        }

        item = buffer[count - 1];
        printf("Consumer consumed %d\n", item);
        count--;

        pthread_mutex_unlock(&mutex);
        pthread_cond_signal(&empty);
    }

    pthread_exit(NULL);
}

int main()
{
    pthread_t tid1, tid2;

    srand(time(NULL));

    pthread_create(&tid1, NULL, producer, NULL);
    pthread_create(&tid2, NULL, consumer, NULL);

    pthread_join(tid1, NULL);
    pthread_join(tid2, NULL);

    return 0;
}

该代码创建了两个线程，一个是生产者，另一个是消费者。生产者每次生产一个随机数，存放到buffer中，每次生产后调用pthread_cond_signal(&full)唤醒等待在full条件变量上的消费者线程。如果buffer已满，则等待在empty条件变量上，等待消费者消费。消费者每次从buffer中取出一个随机数，如果buffer为空则等待在full条件变量上，等待生产者生产。每次消费后调用pthread_cond_signal(&empty)唤醒等待在empty条件变量上的生产者线程。