c++ pthread怎么实现线程间通信

在C++中使用pthread库实现线程间通信，可以使用互斥锁（mutex）、条件变量（condition variable）和信号量（semaphore）等同步机制。以下是使用互斥锁和条件变量实现线程间通信的示例代码：

#include <iostream>#include <pthread.h>int shared_data = 0;pthread_mutex_t mutex;pthread_cond_t cond;void* producer(void* arg) {    for(int i = 0; i < 5; i++) {        pthread_mutex_lock(&mutex);        shared_data = i;        std::cout << "Produced: " << i << std::endl;        pthread_cond_signal(&cond);        pthread_mutex_unlock(&mutex);        sleep(1);    }    pthread_exit(NULL);}void* consumer(void* arg) {    for(int i = 0; i < 5; i++) {        pthread_mutex_lock(&mutex);        while(shared_data == 0) {            pthread_cond_wait(&cond, &mutex);        }        std::cout << "Consumed: " << shared_data << std::endl;        shared_data = 0;        pthread_mutex_unlock(&mutex);    }    pthread_exit(NULL);}int main() {    pthread_t producer_thread, consumer_thread;        pthread_mutex_init(&mutex, NULL);    pthread_cond_init(&cond, NULL);        pthread_create(&producer_thread, NULL, producer, NULL);    pthread_create(&consumer_thread, NULL, consumer, NULL);        pthread_join(producer_thread, NULL);    pthread_join(consumer_thread, NULL);        pthread_mutex_destroy(&mutex);    pthread_cond_destroy(&cond);        return 0;}

在上面的示例代码中，通过互斥锁保护共享数据shared_data，生产者线程将数据写入shared_data，并发送信号通知消费者线程；消费者线程在收到信号后从shared_data中读取数据。通过条件变量实现线程的等待和通知。