sched_yield(3)						     Library Functions Manual						    sched_yield(3)

NAME

       sched_yield - Signals scheduler a willingness to yield to another thread.

LIBRARY

       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS

       #include <pthread.h>

       void   sched_yield(void);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       IEEE Std 1003.1c-1995, POSIX System Application Program Interface

PARAMETERS

       None

DESCRIPTION

       This  routine forces the running thread to relinquish the processor until it again becomes the head of its thread list.	This routine noti-
       fies the thread scheduler that the current thread is willing to release its processor to other threads of equivalent or greater	scheduling
       precedence.   (A  thread generally will release its processor to a thread of a greater scheduling precedence without calling this routine.)
       If no other threads of equivalent or greater scheduling precedence are ready to execute, the thread continues.

       This routine can allow knowledge of the details of an application to be used to improve	its  performance.   If	a  thread  does  not  call
       sched_yield,  other  threads  may  be  given  the opportunity to run at arbitrary points (possibly even when the interrupted thread holds a
       required resource).  By making strategic calls to sched_yield, other threads can be given the opportunity to run  when  the  resources  are
       free.  This can sometimes improve performance by reducing contention for the resource.

       As  a  general  guideline, consider calling this routine after a thread has released a resource (such as a mutex) that is heavily contended
       for by other threads.  This can be especially important if the program is running on a uniprocessor machine, or if the thread acquires  and
       releases the resource inside a tight loop.

       Use  this  routine carefully and sparingly, because misuse can cause unnecessary context switching which will increase overhead and degrade
       performance. For example, it is counter-productive for a thread to yield while it holds a resource that the threads to which it is yielding
       will need.  Likewise, it is pointless to yield unless there is likely to be another thread that is ready to run.

RETURN VALUES

       None

RELATED INFORMATION

       Functions: pthread_attr_setschedparam(3), pthread_setschedparam(3)

       Manuals: Guide to DECthreads and Programmer's Guide

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																    sched_yield(3)