线程分离以后的资源回收

#include <iostream>
#include <thread>
#include <chrono>

using namespace std;
using namespace std::chrono;

struct A {
    A() { cout << "A::A()" << endl; }
    ~A() { cout << "A::~A() " << endl; }
};

void child() {
    A a;
    cout << "child" << endl;
    this_thread::sleep_for(chrono::seconds(3));
}

void parent() {
    cout << "parent" << endl;
    thread t{child};
    t.detach();
//    this_thread::sleep_for(chrono::seconds(1));
}

int main() {
    parent();
    cout << "main" << endl;
//    this_thread::sleep_for(chrono::seconds(5));
    return 0;
}

线程detach以后，如果进程结束（比如main函数返回）则该detached线程的资源交给系统回收，与该线程的父线程是否返回无关（除非父线程是main函数）