C++-mutex(待验证)

Posted 2023-06-02

C++-mutex(待验证)

在使用std::mutex时，应该声明为全局或者类的静态成员变量。

class A

public:
  void f();
public:
  static std::mutex m_Mutex;


std::mutex _mu;
void A:f()

  std::lock_guard<std::mutex> guard1(_mu);
  ;


void A:f2()

  _mu.lock();
  ;
  _mu.unlock();

本文来自博客园，作者：Theseus‘Ship，转载请注明原文链接：https://www.cnblogs.com/yongchao/p/17450662.html

c使用mutex同步

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

void increase();

int sum = 0;

pthread_mutex_t mutex;

int main() {
    // init mutex
    pthread_mutex_init(&mutex, NULL);
    pthread_t threads[4];
    for (int i = 0; i < sizeof(threads) / sizeof(threads[0]); i++) {
        pthread_create(&threads[i], NULL, increase, NULL);
    }

    for (int i = 0; i < sizeof(threads) / sizeof(threads[0]); i++) {
        void *joinstatus;
        int res = pthread_join(threads[i], &joinstatus);
        printf("res:%d
", res);
        if (res) {
//            fprintf(stderr, "pthread_join fail");
            perror("pthread_join fail");
        }
    }
//    sleep(2);
    pthread_mutex_destroy(&mutex);
    printf("sum:%d
", sum);
    return 0;
}

void increase() {
    for (int i = 0; i < 10000; i++) {
        pthread_mutex_lock(&mutex);
        sum++;
        pthread_mutex_unlock(&mutex);
    }
    printf("t_id:%u
", pthread_self());
}

pthread_joint开始传的&thread，指针类型，编译和运行都没有报错，函数返回3。改成pthread_t类型的可以了