用c语言编程实现生产者-消费者问题的模拟

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

#define BUFFER_SIZE 10

int buffer[BUFFER_SIZE];
int count = 0;
int in = 0, out = 0;

sem_t full, empty;
pthread_mutex_t mutex;

void *producer(void *param);
void *consumer(void *param);

int main(int argc, char *argv[]) {
    pthread_t producer_tid, consumer_tid;
    pthread_attr_t attr;
    pthread_attr_init(&attr);

    sem_init(&full, 0, 0);
    sem_init(&empty, 0, BUFFER_SIZE);
    pthread_mutex_init(&mutex, NULL);

    pthread_create(&producer_tid, &attr, producer, NULL);
    pthread_create(&consumer_tid, &attr, consumer, NULL);

    pthread_join(producer_tid, NULL);
    pthread_join(consumer_tid, NULL);

    sem_destroy(&full);
    sem_destroy(&empty);
    pthread_mutex_destroy(&mutex);

    pthread_exit(NULL);
}

void *producer(void *param) {
    int item;
    while (1) {
        item = rand() % 100;
        sem_wait(&empty);
        pthread_mutex_lock(&mutex);
        buffer[in] = item;
        printf("Producer %lu: write %d into buffer[%d]\n", pthread_self(), item, in);
        in = (in + 1) % BUFFER_SIZE;
        count++;
        pthread_mutex_unlock(&mutex);
        sem_post(&full);
        sleep(rand() % 5);
    }
}

void *consumer(void *param) {
    int item;
    while (1) {
        sem_wait(&full);
        pthread_mutex_lock(&mutex);
        item = buffer[out];
        printf("Consumer %lu: read %d from buffer[%d]\n", pthread_self(), item, out);
        out = (out + 1) % BUFFER_SIZE;
        count--;
        pthread_mutex_unlock(&mutex);
        sem_post(&empty);
        sleep(rand() % 5);
    }
}

上述代码实现了一种比较简单的生产者-消费者问题的模拟。其中，使用了信号量和互斥量来控制缓冲区中元素的生产和消费过程。在生产者线程中，生成一个随机数代表一个生产元素，如果缓冲区未满，就将元素加入到缓冲区中，并将in指针指向下一个位置，count加1。在消费者线程中，如果缓冲区不为空，就将元素从缓冲区中取出，将out指针指向下一个位置，count减1。

注意，真实生产环境中需要更严密的错误处理和同步。