std::thread

td::thread 各种构造函数例子如下：

#include <iostream>
#include <utility>
#include <thread>
#include <chrono>
#include <functional>
#include <atomic>

void f1(int n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread " << n << " executing
";
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}

void f2(int& n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread 2 executing
";
        ++n;
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}

int main()
{
    int n = 0;
    std::thread t1; // t1 is not a thread
    std::thread t2(f1, n + 1); // pass by value
    std::thread t3(f2, std::ref(n)); // pass by reference
    std::thread t4(std::move(t3)); // t4 is now running f2(). t3 is no longer a thread
    t2.join();
    t4.join();
    std::cout << "Final value of n is " << n << '
';
}

root@ubuntu:~/c++#  g++ -std=c++11 -pthread obj.cpp  -o obj
root@ubuntu:~/c++# ./obj 
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Final value of n is 5
root@ubuntu:~/c++# 

 

int main()
{
    int n = 0;
    std::thread t1; // t1 is not a thread
    std::thread t2(f1, n + 1); // pass by value
    std::thread t3(f2, std::ref(n)); // pass by reference
    t2.join();
    t3.join();
    std::thread t4(std::move(t3)); // t4 is now running f2(). t3 is no longer a thread
    t4.join();
    std::cout << "Final value of n is " << n << '
';
}

root@ubuntu:~/c++#  g++ -std=c++11 -pthread obj.cpp  -o obj
root@ubuntu:~/c++# ./obj 
Thread Thread 2 executing
1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
terminate called after throwing an instance of 'std::system_error'
  what():  Invalid argument
Aborted
root@ubuntu:~/c++# 

int main()
{
    int n = 0;
    std::thread t1; // t1 is not a thread
    std::thread t2(f1, n + 1); // pass by value
    std::thread t3(f2, std::ref(n)); // pass by reference
    t2.join();
    t3.join();
    std::thread t4(std::move(t3)); // t4 is now running f2(). t3 is no longer a thread
    //t4.join();
    std::cout << "Final value of n is " << n << '
';
}

root@ubuntu:~/c++#  g++ -std=c++11 -pthread obj.cpp  -o obj
root@ubuntu:~/c++# ./obj 
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Final value of n is 5
root@ubuntu:~/c++# 

std::thread 赋值操作

Move 赋值操作	thread& operator=(thread&& rhs) noexcept;
拷贝赋值操作 [deleted]	thread& operator=(const thread&) = delete;

• Move 赋值操作(1)，如果当前对象不可 joinable，需要传递一个右值引用(rhs)给 move 赋值操作；如果当前对象可被 joinable，则会调用 terminate() 报错。
• 拷贝赋值操作(2)，被禁用，因此 std::thread 对象不可拷贝赋值。

#include <iostream>
#include <utility>
#include <thread>
#include <chrono>
#include <functional>
#include <atomic>
#include <vector>
std::vector<std::thread> vthreads;
int n=0;
void f1(int n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread " << n << " executing
";
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}

void f2(int& n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread 2 executing
";
        ++n;
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}

int create_thread()
{
    std::thread t2(f1, n + 1); // pass by value
    std::thread t3(f2, std::ref(n)); // pass by reference
    vthreads.push_back(std::move(t2));
    vthreads.push_back(std::move(t3));
}
int main()
{
    create_thread();
   // for(auto it = vthreads.begin(); it != vthreads.end(); ++it)
   // {
   //                 it->join();
   // }

   for ( auto & th :vthreads)
   {
           th.join();
   }
   std::cout << "Final value of n is " << n << '
';
   return 0;
}

root@ubuntu:~/c++#  g++ -std=c++11 -pthread obj.cpp  -o obj
root@ubuntu:~/c++# ./obj 
Thread Thread 2 executing
1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Thread 2 executing
Thread 1 executing
Final value of n is 5