osf1 man page for pthread_attr_setschedparam

pthread_attr_setschedparam(3)				     Library Functions Manual				     pthread_attr_setschedparam(3)

NAME
       pthread_attr_setschedparam  -  Changes  the values of the parameters associated with a scheduling policy of the specified thread attributes
       object.

LIBRARY
       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS
       #include <pthread.h>

       int pthread_attr_setschedparam(
			pthread_attr_t		   *attr,
			const struct sched_param   *param);

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

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

PARAMETERS
       Thread attributes object for the scheduling policy whose parameters are to be set.  A structure containing new values for scheduling param-
       eters  associated  with	the scheduling policy attribute of the specified thread attributes object.  Note that DECthreads provides only the
       sched_priority scheduling parameter.  See the Description section for information about this scheduling parameter.

DESCRIPTION
       This routine sets the scheduling parameters associated with the scheduling policy attribute of the thread attributes  object  specified	by
       the attr argument.

       Use  the  sched_priority  field of a sched_param structure to set a thread's execution priority.  The effect of the scheduling priority you
       assign depends on the scheduling policy specified for the attributes object specified by the attr argument.

       By default, a created thread inherits the priority of the thread calling pthread_create(3).  To specify	a  priority  using  this  routine,
       scheduling  inheritance	must be disabled at the time the thread is created.  Before calling pthread_create(3), call pthread_attr_setinher-
       itsched(3) and specify the value PTHREAD_EXPLICIT_SCHED for the inherit argument.

       An application specifies priority only to express the urgency of executing the thread relative to other threads.  DO NOT  USE  PRIORITY	TO
       CONTROL MUTUAL EXCLUSION WHEN ACCESSING SHARED DATA.  With a sufficient number of processors present, all ready threads, regardless of pri-
       ority, execute simultaneously.

       Valid values of the sched_priority scheduling parameter depend on the chosen scheduling policy.	Use the  POSIX	routines  sched_get_prior-
       ity_min(3) or sched_get_priority_max(3) to determine the low and high limits of each policy.

       Additionally,  DECthreads  provides nonportable priority range constants, as follows: PRI_FIFO_MIN to PRI_FIFO_MAX PRI_RR_MIN to PRI_RR_MAX
       PRI_OTHER_MIN to PRI_OTHER_MAX PRI_FG_MIN_NP to PRI_FG_MAX_NP PRI_BG_MIN_NP to PRI_BG_MAX_NP

       The default priority varies by DECthreads platform.  On Tru64 UNIX, the default is 19 (that is, the POSIX priority of  a  normal  timeshare
       process).  On other platforms, the default priority is the midpoint between PRI_FG_MIN_NP and PRI_FG_MAX_NP.

RETURN VALUES
       If  an  error condition occurs, this routine returns an integer value indicating the type of error.  Possible return values are as follows:
       Successful completion.  The value specified by param is not a valid thread attributes object, or the value specified by param  is  invalid.
       An attempt was made to set the attribute to an unsupported value.

ERRORS
       None

RELATED INFORMATION
       Functions:    pthread_attr_init(3),    pthread_attr_getschedparam(3),	pthread_attr_setinheritsched(3),   pthread_attr_setschedpolicy(3),
       pthread_create(3), sched_yield(3)

       Manuals: Guide to DECthreads and Programmer's Guide

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														     pthread_attr_setschedparam(3)