Description

   In conformance with the IEEE POSIX.1-1996 standard, the sched_
   yield() function causes the calling thread to yield execution
   to another thread. It is useful when a thread running under the
   SCHED_FIFO scheduling policy must allow another thread at the
   same priority to run. The thread that is interrupted by sched_
   yield() goes to the end of the queue for its priority.

   If no other thread is runnable at the priority of the calling
   thread, the calling thread continues to run.

   Threads with higher priority are allowed to preempt the calling
   thread, so the sched_yield() function has no effect on the
   scheduling of higher- or lower-priority threads.

   The sched_yield() routine takes no arguments. No special
   privileges are needed to use the sched_yield() function.