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.
On error, -1 is returned, and
is set appropriately.
In the Linux implementation,
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
POSIX systems on which
is available define
Strategic calls to
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.
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.