我实例化它开始运行的std::thread
(即调用工作函数),或者只在我调用join()
时才开始运行,这在文档中有点不清楚。
答案 0 :(得分:2)
它将在您实例化时执行。
使用连接,以便当前线程将等到另一个线程完成执行。
来自http://en.cppreference.com/w/cpp/thread/thread/thread
的一些示例代码 void f1(int n)
{
for (int i = 0; i < 5; ++i) {
std::cout << "Thread 1 executing\n";
++n;
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";
++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 << '\n';
}
Possible output:
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 2 executing
Thread 1 executing
Final value of n is 5
答案 1 :(得分:1)
创建std::tread
后,它处于运行状态,可以执行指令。
无法保证它会在任何给定的时间间隔内完成任何事情,但随着时间间隔变得越来越长,它会做出更接近100%的概率。
通常,生动的设计实际上保证了当你达到十分之几秒的间隔时,所有非等待的线程都会表现出一些活动。