pthread_attr_setschedparam(3) [osf1 man page]

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

       delim off

														     pthread_attr_setschedparam(3)

pthread_setschedparam(3)				     Library Functions Manual					  pthread_setschedparam(3)

NAME

       pthread_setschedparam - Changes a thread's scheduling policy and scheduling parameters.

LIBRARY

       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS

       #include <pthread.h>

       int  pthread_setschedparam(
			  pthread_t		     thread,
			  int			     policy,
			  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 whose scheduling policy and parameters are to be changed.  New scheduling policy value for the thread specified in thread.  The fol-
       lowing are valid values: SCHED_BG_NP SCHED_FG_NP SCHED_FIFO SCHED_OTHER SCHED_RR See Guide to DECthreads for a description of the  schedul-
       ing  policies.	New  values  of the scheduling parameters associated with the scheduling policy for the thread specified in thread.  Valid
       values for the sched_priority field  of	a  sched_param	structure  depend  on  the  chosen  scheduling	policy.  Use  the  POSIX  routines
       sched_get_priority_min(3)  or  sched_get_priority_max(3) to determine the low and high limits of each policy. Additionally, DECthreads pro-
       vides nonportable priority range constants, as follows: PRI_FIFO_MIN (low) to PRI_FIFO_MAX (high) PRI_RR_MIN  (low)  to	PRI_RR_MAX  (high)
       PRI_OTHER_MIN  (low)  to  PRI_OTHER_MAX	(high) PRI_FG_MIN_NP (low) to PRI_FG_MAX_NP (high) PRI_BG_MIN_NP (low) to PRI_BG_MAX_NP (high) 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 the non-UNIX platforms, the default priority is the midpoint between PRI_FG_MIN_NP and PRI_FG_MAX_NP.

DESCRIPTION

       This  routine changes both the current scheduling policy and associated scheduling parameters of the thread specified by thread to the pol-
       icy and associated parameters provided in policy and param, respectively.

       All currently implemented DECthreads scheduling policies have one scheduling parameter called sched_priority.  For the policy  you  choose,
       you must specify an appropriate value in the sched_priority field of the sched_param structure.

       Changing  the  scheduling policy or priority, or both, of a thread can cause it to start executing or to be preempted by another thread.  A
       thread changes its own scheduling policy and priority by using the handle returned by the pthread_self(3) routine.

       This routine differs from pthread_attr_setschedpolicy(3) and pthread_attr_setschedparam(3), in that those routines set the scheduling  pol-
       icy  and  parameter attributes that are used to establish the scheduling priority and scheduling policy of a new thread when it is created.
       However, this routine changes the scheduling policy and parameters of an existing thread.

RETURN VALUES

       If an error condition occurs, no scheduling policy or parameters are changed for the target thread, and this  routine  returns  an  integer
       value  indicating the type of error.  Possible return values are as follows: Successful completion.  The value specified by policy or param
       is invalid.  An attempt was made to set the scheduling policy or a parameter to an unsupported value.  The caller does not have the  appro-
       priate  privileges  to set the scheduling policy or parameters of the specified thread.	The value specified by thread does not refer to an
       existing thread.

ERRORS

       None

RELATED INFORMATION

       Functions: pthread_attr_setschedparam(3), pthread_attr_setschedpolicy(3), pthread_create(3), pthread_self(3), sched_yield(3)

       Manuals: Guide to DECthreads and Programmer's Guide delim off

															  pthread_setschedparam(3)