thrd_yield - cppreference.com (original) (raw)

| | | | | ----------------------- | | ----------- | | void thrd_yield(void); | | (since C11) |

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.

The POSIX equivalent of this function is sched_yield.

[edit] Example

#include <stdio.h> #include <time.h> #include <threads.h> // utility function: difference between timespecs in microseconds double usdiff(struct timespec s, struct timespec e) { double sdiff = difftime(e.tv_sec, s.tv_sec); long nsdiff = e.tv_nsec - s.tv_nsec; if(nsdiff < 0) return 1000000*(sdiff-1) + (1000000000L+nsdiff)/1000.0; else return 1000000*(sdiff) + nsdiff/1000.0; } // busy wait while yielding void sleep_100us() { struct timespec start, end; timespec_get(&start, TIME_UTC); do { thrd_yield(); timespec_get(&end, TIME_UTC); } while(usdiff(start, end) < 100.0); } int main() { struct timespec start, end; timespec_get(&start, TIME_UTC); sleep_100us(); timespec_get(&end, TIME_UTC); printf("Waited for %.3f us\n", usdiff(start, end)); }

Possible output:

[edit] References