举例C++程序在线程出错后重启线程

在C++中，当一个线程出现错误时，可以通过捕获异常并重新启动线程来实现自动重启线程的功能。以下是一个简单的例子，展示了如何实现这一功能：

#include <iostream>
#include <thread>
#include <exception>
#include <chrono>
#include <atomic>

std::atomic<bool> threadFailed(false);
std::atomic<bool> shouldExit(false);

void threadFunction() {
    static int counter = 0;
    counter++;
    std::cout << "Thread started, attempt " << counter << std::endl;

    if (counter < 2) {
        // 模拟异常
        throw std::runtime_error("Thread encountered an error");
    }

    std::cout << "Thread completed successfully" << std::endl;
}

void monitoredThread() {
    try {
        threadFunction();
    } catch (const std::exception& e) {
        std::cerr << "Exception in monitored thread: " << e.what() << std::endl;
        threadFailed = true; // 设置标志，通知监控线程
    }
}

void monitorThread() {
    while (!shouldExit) {
        if (threadFailed) {
            std::cerr << "Restarting monitored thread..." << std::endl;
            threadFailed = false; // 重置标志
            std::thread t(monitoredThread);
            t.detach(); // 使新线程独立运行
        }
        std::this_thread::sleep_for(std::chrono::milliseconds(100)); // 定期检查线程状态
    }
}

int main() {
    std::thread monitor(monitorThread);
    monitor.detach(); // 使监控线程独立运行

    std::thread t(monitoredThread);
    t.join(); // 等待被监控线程第一次完成

    // 等待一定时间，以便监控线程可以运行和重启线程
    std::this_thread::sleep_for(std::chrono::seconds(5));

    shouldExit = true; // 通知监控线程可以退出

    std::cout << "Main thread finished" << std::endl;
    return 0;
}