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pthread_yield_np(3)
NAME
  pthread_yield_np - Notifies the scheduler that the current thread is
  willing to release its processor to other threads of the same or higher
  priority

SYNOPSIS
  #include <pthread.h>

  int pthread_yield_np(
	  void );

LIBRARY
  DECthreads POSIX 1003.1c Library (libpthread.so)

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 notifies 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
  pthread_yield_np(3), 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 pthread_yield_np(3),
  other threads may be given the opportunity to run when the resources are
  free. This improves 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) which 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 actually
  degrade performance.	For example, it is counter-productive for a thread to
  yield while it holds a resource which the threads to which it is yielding
  will need. Likewise, it is pointless to yield unless there is likely to be
  another thread which is ready to run.

RETURN VALUES
  If an error condition occurs, this routine returns an integer value
  indicating the type of error. Possible return values are as follows:

  0   Successful completion.

  [ENOSYS]
      The routine is not supported by this implementation.

ERRORS
  None

SEE ALSO
  Functions: pthread_attr_setschedparam(3), pthread_setschedparam(3),
  pthread_getscheduler(3)

  Manuals: Guide to DECthreads and Programmer's Guide

Index for Section 3

Alphabetical listing for P

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