C++ std::this_thread::yield()函数（线程抑制线程让步让出时间片）volatile

Posted 2022-06-06 Dontla

文章目录

• • mancpp std::this_thread::yield

mancpp std::this_thread::yield

std::this_thread::yield(3)                                            C++ Programmer's Manual                                            std::this_thread::yield(3)



NAME
       std::this_thread::yield - Yield to other threads

TYPE
       function

SYNOPSIS
       #include <thread>

       void yield() noexcept;

DESCRIPTION
       The calling thread yields, offering the implementation the opportunity to reschedule.
       This function shall be called when a thread waits for other threads to advance without blocking.
       //调用线程让步，为实现提供重新调度的机会。
        //当一个线程等待其他线程无阻塞地前进时，应调用此函数。

PARAMETERS
       none

RETURN VALUE
       none

EXAMPLE
         // this_thread::yield example
         #include <iostream>       // std::cout
         #include <thread>         // std::thread, std::this_thread::yield
         #include <atomic>         // std::atomic
         std::atomic<bool> ready (false);
         void count1m(int id) 
           while (!ready)              // wait until main() sets ready...
             std::this_thread::yield();
           
           for (volatile int i=0; i<1000000; ++i) 
           std::cout << id;
         
         int main ()
         
           std::thread threads[10];
           std::cout << "race of 10 threads that count to 1 million:\\n";
           for (int i=0; i<10; ++i) threads[i]=std::thread(count1m,i);
           ready = true;               // go!
           for (auto& th : threads) th.join();
           std::cout << '\\n';
           return 0;
         

       Possible output (last line may vary):
         race of 10 threads that count to 1 million...
         6189370542


EXCEPTION SAFETY
       No-throw guarantee: never throws exceptions.

SEE ALSO
       sleep_until(3)
              Sleep until time point  (function)

       sleep_for(3)
              Sleep for time span  (function)

REFERENCE
       cplusplus.com, 2000-2015 - All rights reserved.



cplusplus.com                                                                2022-05-13                                                  std::this_thread::yield(3)
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