写一个c语言管程解决生产者消费者问题的代码程序

在C语言中，我们可以使用互斥锁（mutex）、条件变量（condition variable）和信号量（semaphore）来解决生产者-消费者问题。这里是一个简单的基于Pthreads库的示例：

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

#define MAX_BUFFER 10
#define SEMAPHORE_INIT 1

typedef struct {
    int buffer[MAX_BUFFER];
    int count;
    int in_prod;
    int in_cons;
    pthread_mutex_t mutex; // 互斥锁
    pthread_cond_t empty, full; // 条件变量
    sem_t semaphore_buffer, semaphore_prod, semaphore_cons;
} Buffer;

void* producer(void* arg) {
    Buffer* buffer = (Buffer*)arg;
    while (1) {
        pthread_mutex_lock(&buffer->mutex);
        if (buffer->count == MAX_BUFFER) {
            pthread_cond_wait(&buffer->full, &buffer->mutex);
        }
        buffer->buffer[buffer->in_prod] = buffer->count++;
        buffer->in_prod = (buffer->in_prod + 1) % MAX_BUFFER;
        printf("Producer produced item %d\n", buffer->count);
        pthread_mutex_unlock(&buffer->mutex);
    }
    return NULL;
}

void* consumer(void* arg) {
    Buffer* buffer = (Buffer*)arg;
    while (1) {
        pthread_mutex_lock(&buffer->mutex);
        if (buffer->count == 0) {
            pthread_cond_wait(&buffer->empty, &buffer->mutex);
        }
        buffer->count--;
        buffer->in_cons = (buffer->in_cons + 1) % MAX_BUFFER;
        printf("Consumer consumed item %d\n", buffer->count);
        pthread_mutex_unlock(&buffer->mutex);
    }
    return NULL;
}

int main() {
    Buffer buffer;
    for (int i = 0; i < MAX_BUFFER; i++) {
        buffer.buffer[i] = -1;
    }
    buffer.count = 0;
    buffer.in_prod = 0;
    buffer.in_cons = 0;
    pthread_init(&buffer.semaphore_buffer, NULL, SEMAPHORE_INIT);
    pthread_mutex_init(&buffer.mutex, NULL);
    pthread_cond_init(&buffer.empty, NULL);
    pthread_cond_init(&buffer.full, NULL);

    pthread_t producer_thread, consumer_thread;
    pthread_create(&producer_thread, NULL, producer, &buffer);
    pthread_create(&consumer_thread, NULL, consumer, &buffer);

    pthread_join(producer_thread, NULL);
    pthread_join(consumer_thread, NULL);

    return 0;
}

这个程序创建了两个线程：生产者负责填充缓冲区，消费者负责消费缓冲区。`mutex`确保并发控制，`cond`确保线程之间的同步。当缓冲区满或空时，线程会等待直到条件满足。