Wake up a std::thread from usleep

Question

Consider the following example:

#include 
#include 
#include 

#include 
#include 

         


        

Answer 1

No, it is not possible using the threads from the standard library.

One possible workaround is to use condition_variable::sleep_for along with a mutex and a boolean condition.

#include 
#include 
#include 

std::mutex mymutex;
std::condition_variable mycond;
bool flag = false;

void sleepy() {
     std::unique_lock lock(mymutex);
     mycond.wait_for( lock,
                      std::chrono::seconds(1000),
                      []() { return flag; } );
}

int main()
{
    std :: thread sleepy_thread(sleepy);

    {
       std::lock_guard lock(mymutex);
       flag = true;
       mycond.notify_one();
    }

    sleepy_thread.join();
}

Alternatively, you can use the Boost.Thread library, which implements the interruption-point concept:

#include 

void sleepy()
{
    // this_thread::sleep_for is an interruption point.
    boost::this_thread::sleep_for( boost::chrono::seconds(1000) );
}

int main()
{
    boost::thread t( sleepy );

    t.interrupt();
    t.join();

}