thread02

// 参数的传递
// thread 构造函数无视函数期待的参数类型，并盲目的拷贝已提供的变量
// std::ref()来解决引用的问题，同bind()时作用
// 可以使用std::function 和bind()来生成可调用对象
#include<iostream>
#include<thread>
#include<functional>
#include<cstring>
struct widget_data
{
  std::string str;
  int int_data;  
};

void updata_data_for_widget(widget_data& data,std::string str,int int_data)
{
    data.str=str;
    data.int_data=int_data;
    std::cout<<"thread id "<<std::this_thread::get_id()<<"\n";
}

int main()
{
    widget_data data;
    std::cout<<"thread id "<<std::this_thread::get_id()<<"\n";
    data.str="a";
    data.int_data=1;
    std::cout<<"before "<<data.str<<" "<<data.int_data<<"\n";
    std::thread my_thread(updata_data_for_widget,std::ref(data),"b",2);
    my_thread.join();
    std::cout<<"after "<<data.str<<" "<<data.int_data<<"\n";
    
    std::function<void(std::string,int)> func_1=bind(updata_data_for_widget,std::ref(data),std::placeholders::_1,std::placeholders::_2);
    std::thread my_thread_1(func_1,"c",3);
    my_thread_1.join();
    // my_thread_1.detach();
    std::cout<<"func_1 after "<<data.str<<" "<<data.int_data<<"\n";
    return 0;
}

// before a 1
// after b 2
// func_1 after c 3