C++知识点-线程2-线程管理

线程管理就是使用join或detach来管理线程。

第一个版本,注意在异常中增加对线程的join

#include <iostream>
#include <thread>
using namespace std;

void function_1(){
    std::cout<<"beauty is only skin-deep"<<std::endl;
}

int main(){
    std::thread t1(function_1); //t1 starts ruing
    try{
    }catch(...){
        t1.join();
        throw;
    }
    t1.join();
    return 0;
}

第二个版本,包一层

#include <iostream>
#include <thread>
using namespace std;

class Fctor{
public:
    void operator()(){
        for(int i = 0; i >-100; i--){
            cout<<"from t1 "<<i<<endl;
        }
    }
};

int main(){
    std::thread t1((Fctor())); //t1 starts ruing
    try{
    }catch(...){
        t1.join();
        throw;
    }
    t1.join();
    return 0;
}

第三个版本,包装层传参

#include <iostream>
#include <thread>
using namespace std;

class Fctor{
public:
    void operator()(string &msg){
        cout<<"t1 says "<<msg<<endl;
        msg = "Trust is the mother of deceit."
    }
};

int main(){
    string s = "where there is no trust, there is no love";
    std::thread t1((Fctor()), s); //t1 starts ruing

    try{
    }catch(...){
        t1.join();
        throw;
    }
    t1.join();

    cout<<"from main: "<<s<<endl;
    return 0;
}

这个版本引用没有起作用,如果想用引用起作用,需要写成下边这样

#include <iostream>
#include <thread>
using namespace std;

class Fctor {
public:
	void operator()(string &msg) {
		std::cout << "t1 says "<<msg.c_str() << endl;
		msg = "Trust is the mother of deceit.";
	}
};

int main() {
	string s = "where there is no trust, there is no love";
	std::thread t1((Fctor()), std::ref(s)); //t1 starts ruing

	try {
	}
	catch (...) {
		t1.join();
		throw;
	}
	t1.join();

	cout << "from main: " << s.c_str() <<endl;
	return 0;
}

底层内存移动的话,可以写成这样

#include <iostream>
#include <thread>
using namespace std;

class Fctor {
public:
	void operator()(string &msg) {
		std::cout << "t1 says "<<msg.c_str() << endl;
		msg = "Trust is the mother of deceit.";
	}
};

int main() {
	string s = "where there is no trust, there is no love";
	std::thread t1((Fctor()), std::move(s)); //t1 starts ruing

	try {
	}
	catch (...) {
		t1.join();
		throw;
	}
	t1.join();

	cout << "from main: " << s.c_str() <<endl;
	return 0;
}

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