c++如何使用mutex来保护共享数据_c++多线程数据同步与互斥锁使用示例

#include <iostream>
#include <thread>
#include <mutex>
#include <vector>

int shared_counter = 0;
std::mutex mtx;  // 定义互斥锁

void increment_counter(int iterations) {
    for (int i = 0; i < iterations; ++i) {
        mtx.lock();           // 加锁
        ++shared_counter;     // 访问共享数据
        mtx.unlock();         // 解锁
    }
}

int main() {
    std::vector<std::thread> threads;
    const int num_threads = 5;
    const int inc_per_thread = 1000;

    for (int i = 0; i < num_threads; ++i) {
        threads.emplace_back(increment_counter, inc_per_thread);
    }

    for (auto& t : threads) {
        t.join();
    }

    std::cout << "Final counter value: " << shared_counter << std::endl;
    return 0;
}

void safe_increment(int iterations) {
    for (int i = 0; i < iterations; ++i) {
        std::lock_guard<std::mutex> guard(mtx);  // 自动加锁
        ++shared_counter;                        // 操作共享数据
    } // guard 离开作用域，自动解锁
}