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# std::this_thread::yield

From cppreference.com
< cpp‎ | thread

Defined in header `<thread>` |  |
void yield(); |  | (since C++11)

Provides a hint to the implementation to reschedule the execution of threads, allowing other threads to run.

### [edit] Parameters

(none)

### [edit] Return value

(none)

### [edit] Notes

The exact behavior of this function depends on the implementation, in particular on the mechanics of the OS scheduler in use and the state of the system. For example, a first-in-first-out realtime scheduler (`SCHED_FIFO` in Linux) would suspend the current thread and put it on the back of the queue of the same-priority threads that are ready to run (and if there are no other threads at the same priority, `yield` has no effect).

### [edit] Example

Run this code

    #include <iostream>
    #include <chrono>
    #include <thread>

    // "busy sleep" while suggesting that other threads run
    // for a small amount of time
    void little_sleep(std::chrono::microseconds us)
    {
        auto start = std::chrono::high_resolution_clock::now();
        auto end = start + us;
        do {
            std::this_thread::yield();
        } while (std::chrono::high_resolution_clock::now() < end);
    }

    int main()
    {
        auto start = std::chrono::high_resolution_clock::now();

        little_sleep(std::chrono::microseconds(100));

        auto elapsed = std::chrono::high_resolution_clock::now() - start;
        std::cout << "waited for "
                  << std::chrono::duration_cast<std::chrono::microseconds>(elapsed).count()
                  << " microseconds\n";
    }

Possible output:

    waited for 128 microseconds

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