thread

thread是c++标准程序库中的一个头文件，表示线程类，位于std空间中。thread对象初始化给出线程执行函数，线程对象构造完成后即可运行。在默认情况下，c++11中的子线程必须加入到主线程运行，即在主线程（main函数）中调用join函数，这样是为了避免主线程运行完毕后子线程还没有运行完成。

每个程序都至少有一个thread，即main()作为起始thread，而每个新加入的thread都是在已有的thread某个执行点上生成分支。

// ConsoleApplication78.cpp : 定义控制台应用程序的入口点。/*  thread*/#include "stdafx.h"#include<thread>#include<iostream>#include<string>//#include <boost/thread/scoped_thread.hpp>using namespace std;class scoped_thread{thread t;public:explicit scoped_thread(thread _t){//检查子线程是否可加入主线程t =move(_t);if (!t.joinable()){cout <<"子线程不能加入到主线程中" << endl;throw logic_error("not thread");}cout <<"call scoped_thread (thread)"<< endl;}scoped_thread(){cout <<"call scoped_thread ()" << endl;}~scoped_thread(){//对象销毁时，将子线程加入到主线程中cout <<"对象销毁" << endl;t.join();}scoped_thread(scoped_thread const&) = delete;scoped_thread& operator=(scoped_thread const&) = delete;};void do_something(int& i){cout << i << " ";++i;}struct func{int &i;func(int &_i):i(_i){//cout <<"call func()" << endl;};void operator()(){//cout <<"call ()" << endl;for (unsigned j = 0; j < 20; j++){do_something(i);}}};void do_something_in_current_thread(){}//void do_something_with_current_thread(thread& th)//{//  th.join();//}//主线程int _tmain(int argc, _TCHAR* argv[]){int some_local_state = 1;//子线程--将未命名线程对象直接传递给scoped_thread//thread类不允许拷贝scoped_thread t(thread{func(some_local_state) });/*匿名类（仿函数）生成thread类可能会产生歧义*///scoped_thread t(thread(func(some_local_state) ));//在主线程对象t销毁时将子线程加入主线程mian中，do_something_in_current_thread();system("pause");return 0;}