写在前面:

又是学C扎扎的一天，C扎扎学起来果然扎手。如果你能坚持看到文章最后，你会发现，好吧有可能你啥也发现不了，因为后面什么也没有~~~

目录

1. 使用 async 函数创建线程

1.1 使用步骤

1.2 基本数据类型作为返回值

1.3 结构体类型数据作为返回值

1.4 带返回值的类的成员函数作为线程处理函数

1.5async的其它两个参数

2. 使用类模板 packaged_task 打包线程处理函数

2.1使用步骤

2.2普通函数的打包

2.3带参数的普通函数的打包

2.4类的成员函数的打包

2.5 Lambda表达式的打包

3. 使用类模板 promise 获取线程处理函数返回值

3.1使用步骤

3.2 基本数据类型作为返回值返回

3.3结构体类型作为返回值返回

3.4类中带返回值的普通函数作为线程处理函数

1. 使用 async 函数创建线程

1.1 使用步骤

1.2 基本数据类型作为返回值

#include <iostream>#include <thread>#include <future>using namespace std;//1.1 普通类型返回值int returnValue() {return 666;}void test01() {future<int> res = async(returnValue);cout << res.get() << endl;}int main() {system("color F0");test01();return 0;}

1.3 结构体类型数据作为返回值

#include <iostream>#include <thread>#include <future>#include <string>#include <chrono>using namespace std;//结构体类型返回值struct Person {int age;string name;friend ostream& operator<<(ostream& out, Person& person);};// << 运算符重载ostream& operator<<(ostream& out, Person& person) {out << person.age << "\t" << person.name << endl;return out;}Person returnPerson() {Person person = { 18,"张飞" };return person;}void test02() {future<Person> res = async(returnPerson);Person person = res.get();cout << person << endl;}int main() {system("color F0");test02();return 0;}

1.4 带返回值的类的成员函数作为线程处理函数

#include <iostream>#include <thread>#include <future>#include <string>#include <chrono>using namespace std;//1.3 带返回值的类成员函数充当线程处理函数class MM {public:int mmThreadFunc(int num) {cout << "子线程id: " << this_thread::get_id() << endl;num *= 10;//延时chrono::microseconds duration(1000); //1000微秒this_thread::sleep_for(duration);return num;}protected:private:};void test03() {MM mm;future<int> res = async(&MM::mmThreadFunc, &mm, 5);cout << res.get() << endl;}int main() {system("color F0");test03();return 0;}

1.5async的其它两个参数

#include <iostream>#include <thread>#include <future>#include <string>#include <chrono>using namespace std;//1.4 async 的其它参数 ()//launch::async: 创建线程，执行线程处理函数//launch::deferred: 线程处理函数延迟到调用wait和get方法时候才执行，本质开始是没有创建子线程int returnValue2(int num) {cout << "线程处理函数启动....." << endl;return num * 10;}void test04() {MM mm;//auto res = async(launch::async,returnValue2, 6); //默认参数auto res = async(launch::deferred, returnValue2, 6);this_thread::sleep_for(1s); //延时1scout << "---------get前-----------" << endl;cout << res.get() << endl;//cout << res.get() << endl; //注 res只能被get()一次cout << "---------get后-----------" << endl;}int main() {system("color F0");test04();return 0;}

使用launch::async参数结果,创建线程并且执行线程处理函数

使用launch::deferred参数结果,线程处理函数延迟到调用wait和get方法时候才执行，本质开始是没有创建子线程

注:async的返回值 res 只能被 get() 一次

2. 使用类模板 packaged_task 打包线程处理函数

2.1使用步骤

2.2普通函数的打包

#include <iostream>#include <thread>#include <future>using namespace std;int returnValue() {return 666;}//3.1 普通函数的打包void test05() {packaged_task<int(void)> taskOne(returnValue);thread t1(ref(taskOne));t1.join();cout << taskOne.get_future().get() << endl;}int main() {system("color F0");test05();return 0;}

2.3带参数的普通函数的打包

#include <iostream>#include <thread>#include <future>using namespace std;int returnValue2(int num) {cout << "线程处理函数启动....." << endl;return num * 10;}//3.2 带参数普通函数打包void test06() {packaged_task<int(int)> taskOne(bind(returnValue2,placeholders::_1));thread t1(ref(taskOne), 10);t1.join();cout << taskOne.get_future().get() << endl;}int main() {system("color F0");test06();return 0;}

2.4类的成员函数的打包

#include <iostream>#include <thread>#include <future>using namespace std;class MM {public:int mmThreadFunc(int num) {cout << "子线程id: " << this_thread::get_id() << endl;num *= 10;chrono::microseconds duration(1000); //1000微秒this_thread::sleep_for(duration);return num;}};//3.2 类的成员函数的打包void test07() {MM mm;packaged_task<int(int)> taskOne(bind(&MM::mmThreadFunc, &mm, placeholders::_1));thread t1(ref(taskOne), 5);t1.join();cout << taskOne.get_future().get() << endl;}int main() {system("color F0");test07();return 0;}

2.5 Lambda表达式的打包

#include <iostream>#include <thread>#include <future>using namespace std;//3.3 Lambda表达式的打包void test08() {packaged_task<int(int)> taskOne([](int num) {cout << "Lambda表达式线程id: " << this_thread::get_id() << endl;num *= 5;return num;});thread t1(ref(taskOne), 5);t1.join();cout << taskOne.get_future().get() << endl;}int main() {system("color F0");test08();return 0;}

3. 使用类模板 promise 获取线程处理函数返回值

3.1使用步骤

3.2 基本数据类型作为返回值返回

#include <iostream>#include <thread>#include <future>using namespace std;void promiseThread(promise<int>& temp, int data) {cout << "promise id: " << this_thread::get_id() << endl;data *= 10;temp.set_value(data);}void test09() {promise<int> temp;thread t1(promiseThread, ref(temp), 66);t1.join();cout << "promise value: " << temp.get_future().get() << endl;}int main() {system("color F0");test09();return 0;}

#include <iostream>#include <thread>#include <future>using namespace std;//方式2void promsieThread2(future<int>& temp) {cout << "promise id: " << this_thread::get_id() << endl;cout << "子线程: " << temp.get() << endl;}void test10() {promise<int> temp;temp.set_value(666);auto num = temp.get_future();thread t1(promsieThread2, ref(num));t1.join();}int main() {system("color F0");test10();return 0;}

3.3结构体类型作为返回值返回

#include <iostream>#include <thread>#include <future>using namespace std;//结构体类型参数传递struct Person {int age;string name;friend ostream& operator<<(ostream& out, Person& person);};// << 运算符重载ostream& operator<<(ostream& out, Person& person) {out << person.age << "\t" << person.name << endl;return out;}void promiseThread3(promise<Person>& temp, Person data) {cout << "promise id: " << this_thread::get_id() << endl;data.age = 100;data.name = "张三";temp.set_value(data);}void test11() {promise<Person> temp;Person person = { 18,"貂蝉" };thread t1(promiseThread3, ref(temp), person);t1.join();person = temp.get_future().get();cout << person << endl;}int main() {system("color F0");test11();return 0;}

3.4类中带返回值的普通函数作为线程处理函数

#include <iostream>#include <thread>#include <future>using namespace std;//类中带返回值普通函数充当线程处理函数class MM2 {public:void mmThreadFunc(promise<int>& temp, int num) {cout << "子线程id: " << this_thread::get_id() << endl;chrono::microseconds duration(1000); //1000微秒this_thread::sleep_for(duration);temp.set_value(num * 100);}};void test12() {promise<int> temp;MM2 mm;thread t1(&MM2::mmThreadFunc, &mm,ref(temp), 10);t1.join();cout << temp.get_future().get() << endl;}int main() {system("color F0");test12();return 0;}

有一种思念

即便使尽全身的力气

即便站在最忠诚的回音壁前

却依然无法

呼喊出一个人的名字

—―杜拉斯