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在C++ And Beyond 的这篇剪辑的开头附近,我听到了一些关于问题的内容std::async.我有两个问题:

1. 对于初级开发人员,是否有一套规则用于做什么以及在使用时要避免什么std::async？

2. 这个视频有什么问题？它们与本文有关吗？

I'm learning about mutexes in C++ and have a problem with the following code (taken from N. Josuttis' "The C++ Standard Library").

I don't understand why it blocks / throws unless I add this_thread::sleep_for in the main thread (then it doesn't block and all three calls are carried out).

The compiler is cl.exe used from the command line.

#include <future>
#include <mutex>
#include <iostream>
#include <string>
#include <thread>
#include <chrono>

std::mutex printMutex;

void print(const std::string& s)
{
    std::lock_guard<std::mutex> lg(printMutex);

    for …