NAME

       sched_yield - yield the processor

SYNOPSIS

       #include <sched.h>

       int sched_yield(void);

DESCRIPTION

       sched_yield() causes the calling thread to relinquish the CPU.  The thread is moved to the
       end of the queue for its static priority and a new thread gets to run.

RETURN VALUE

       On success, sched_yield() returns  0.   On  error,  -1  is  returned,  and  errno  is  set
       appropriately.

ERRORS

       In the Linux implementation, sched_yield() always succeeds.

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008.

NOTES

       If  the  calling  thread  is the only thread in the highest priority list at that time, it
       will continue to run after a call to sched_yield().

       POSIX systems on which sched_yield() is  available  define  _POSIX_PRIORITY_SCHEDULING  in
       <unistd.h>.

       Strategic  calls  to  sched_yield()  can  improve  performance  by giving other threads or
       processes a chance to run when (heavily) contended resources  (e.g.,  mutexes)  have  been
       released  by  the  caller.   Avoid  calling sched_yield() unnecessarily or inappropriately
       (e.g., when resources needed by other schedulable threads are still held by  the  caller),
       since  doing  so  will  result  in unnecessary context switches, which will degrade system
       performance.

       sched_yield() is intended for use with real-time scheduling policies (i.e., SCHED_FIFO  or
       SCHED_RR).   Use  of  sched_yield()  with  nondeterministic  scheduling  policies  such as
       SCHED_OTHER is unspecified and very likely means your application design is broken.

SEE ALSO

       sched(7)

COLOPHON

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