Linux之信号量 | 消费者生产者模型的循环队列

#include <stdio.h>
#include <stdlib.com>
#include <pthread.h>
#include <semaphore.h>
 
#define BUFFER_SIZE 10
 
typedef struct {
    int buffer[BUFFER_SIZE];
    sem_t empty_count;
    sem_t full_count;
    sem_t mutex;
    int read_pos, write_pos;
} CircularQueue;
 
CircularQueue q;
 
void init_queue(CircularQueue *q) {
    q->read_pos = 0;
    q->write_pos = 0;
    sem_init(&q->empty_count, 0, BUFFER_SIZE);
    sem_init(&q->full_count, 0, 0);
    sem_init(&q->mutex, 0, 1);
}
 
void enqueue(CircularQueue *q, int data) {
    sem_wait(&q->empty_count);
    sem_wait(&q->mutex);
    q->buffer[q->write_pos] = data;
    q->write_pos = (q->write_pos + 1) % BUFFER_SIZE;
    sem_post(&q->mutex);
    sem_post(&q->full_count);
}
 
int dequeue(CircularQueue *q) {
    int data;
    sem_wait(&q->full_count);
    sem_wait(&q->mutex);
    data = q->buffer[q->read_pos];
    q->read_pos = (q->read_pos + 1) % BUFFER_SIZE;
    sem_post(&q->mutex);
    sem_post(&q->empty_count);
    return data;
}
 
int main() {
    init_queue(&q);
    // 生产者消费者线程...
    return 0;
}

这个代码实例提供了一个使用信号量实现的循环队列的简单示例。初始化队列，入队操作和出队操作都被正确地实现，并且使用了适当的信号量来同步访问。这个例子可以作为在Linux环境下实现线程同步和通信的一个基础教学示例。