方法阻塞的解决方案之一-编程知识

1、简单使用

一个h一个cpp文件

#pragma once
#include <iostream>
#include <thread>
#include <atomic>
#include <chrono>
#include <string>class Person {public:struct dog {std::string name;int age;};public:void a(std::atomic<bool>& running, int param1, double param2, const std::string& param3);void startA(int param1, double param2, const std::string& param3);
};

#include <iostream>
#include <thread>
#include <atomic>
#include <chrono>
#include <string>
#include "osg.h"void Person::a(std::atomic<bool>& running, int param1, double param2, const std::string& param3) {std::cout << "Function a started with params " << param1 << ", " << param2 << ", " << param3 << "." << std::endl;// 模拟耗时操作while (running) {// 执行一些操作}std::cout << "Function a ended." << std::endl;
}void Person::startA(int param1, double param2, const std::string& param3) {std::atomic<bool> running(true);// 创建并启动线程std::thread thread_a(&Person::a, this, std::ref(running), param1, param2, param3);std::this_thread::sleep_for(std::chrono::seconds(10));if (running.load()) {std::cout << "stop" << std::endl;running = false;}// 等待线程完成执行if (thread_a.joinable()) {thread_a.join();}
}int main() {Person person;person.startA(42, 3.14, "Hello");// ... 其他代码 ...return 0;}

2、方法A中存在引用

错误示例：

将sum执行的数据保存下来

#include <iostream>
#include <thread>
#include <atomic>
#include <chrono>
#include <string>
#include "osg.h"void Person::a(std::atomic<bool>& running, int& sum, double param2) {std::cout << "Function a started with params " << sum << ", " << param2 << std::endl;// 模拟耗时操作while (running) {// 执行一些操作for (int i = 0; i < 10000000; i++) {sum = i;}}std::cout << "Function a ended." << std::endl;
}void Person::startA(int param1, double param2, const std::string& param3) {for (int i = 0; i < 2; i++) {int sum = 0;std::atomic<bool> running(true);// 创建并启动线程std::thread thread_a(&Person::a, this, std::ref(running), sum, param2);std::this_thread::sleep_for(std::chrono::seconds(5));if (running.load()) {std::cout << "stop" << std::endl;running = false;}// 等待线程完成执行if (thread_a.joinable()) {thread_a.join();std::cout << "等待线程完成执行" << std::endl;}std::cout << "sum: " <<sum<< std::endl;}std::cout << "任务结束" << std::endl;}
int main() {Person person;person.startA(42, 3.14, "Hello");// ... 其他代码 ...return 0;
}

编译都过不去

正确示例：

只修改一句

        std::thread thread_a(&Person::a, this, std::ref(running), std::ref(sum), param2);

#include <iostream>
#include <thread>
#include <atomic>
#include <chrono>
#include <string>
#include "osg.h"void Person::a(std::atomic<bool>& running, int& sum, double param2) {std::cout << "Function a started with params " << sum << ", " << param2 << std::endl;// 模拟耗时操作while (running) {// 执行一些操作for (int i = 0; i < 1000000000; i++) {sum = i;}}std::cout << "Function a ended." << std::endl;
}void Person::startA(int param1, double param2, const std::string& param3) {for (int i = 0; i < 2; i++) {int sum = 0;std::atomic<bool> running(true);// 创建并启动线程std::thread thread_a(&Person::a, this, std::ref(running), std::ref(sum), param2);std::this_thread::sleep_for(std::chrono::seconds(5));if (running.load()) {std::cout << "stop" << std::endl;running = false;}// 等待线程完成执行if (thread_a.joinable()) {thread_a.join();std::cout << "等待线程完成执行" << std::endl;}std::cout << "sum: " <<sum<< std::endl;}std::cout << "任务结束" << std::endl;}
int main() {Person person;person.startA(42, 3.14, "Hello");// ... 其他代码 ...return 0;
}

3、A方法阻塞时间过长，希望停止

如果Person::a 方法卡住了，那么 if (thread_a.joinable()) { thread_a.join(); } 就阻塞了，std::cout << "sum: " <<sum<< std::endl; 值就得不到了，除非a方法完成了

#include <iostream>
#include <thread>
#include <atomic>
#include <chrono>
#include <string>
#include "osg.h"void Person::a(std::atomic<bool>& running, int& sum, const double &param2) {std::cout << "Function a started with params " << sum << ", " << param2 << std::endl;// 模拟耗时操作for (int i = 0; i < 10; i++) {std::this_thread::sleep_for(std::chrono::seconds(1));sum = i;}std::cout << "Function a ended." << std::endl;}void Person::startA(int param1, double param2, const std::string& param3) {for (int i = 0; i < 2; i++) {int sum = 0;std::atomic<bool> running(true);// 创建并启动线程std::thread thread_a(&Person::a, this, std::ref(running), std::ref(sum), param2);std::this_thread::sleep_for(std::chrono::seconds(3));if (running.load()) {std::cout << "stop" << std::endl;running = false;}// 等待线程完成执行if (thread_a.joinable()) {thread_a.join();}std::cout << "sum: " <<sum<< std::endl;}std::cout << "任务结束" << std::endl;}
int main() {Person person;person.startA(42, 3.14, "Hello");// ... 其他代码 ...return 0;
}

修改：

在每次循环、处理小任务、遍历某数据中进行running判断

#include <iostream>
#include <thread>
#include <atomic>
#include <chrono>
#include <string>
#include "osg.h"void Person::a(std::atomic<bool>& running, int& sum, const double &param2) {std::cout << "Function a started with params " << sum << ", " << param2 << std::endl;// 模拟耗时操作for (int i = 0; i < 10; i++) {if (!running) break;std::this_thread::sleep_for(std::chrono::seconds(1));sum = i;}std::cout << "Function a ended." << std::endl;}void Person::startA(int param1, double param2, const std::string& param3) {for (int i = 0; i < 2; i++) {int sum = 0;std::atomic<bool> running(true);// 创建并启动线程std::thread thread_a(&Person::a, this, std::ref(running), std::ref(sum), param2);std::this_thread::sleep_for(std::chrono::seconds(3));if (running.load()) {std::cout << "stop" << std::endl;running = false;}// 等待线程完成执行if (thread_a.joinable()) {thread_a.join();}std::cout << "sum: " <<sum<< std::endl;}std::cout << "任务结束" << std::endl;}
int main() {Person person;person.startA(42, 3.14, "Hello");// ... 其他代码 ...return 0;
}