sched_get_priority_min

GET_PRIORITY_MAX(2)	  Linux Programmer’s Manual	  GET_PRIORITY_MAX(2)



NAME
       sched_get_priority_max,	sched_get_priority_min	- get static priority
       range

SYNOPSIS
       #include <sched.h>

       int sched_get_priority_max(int policy);

       int sched_get_priority_min(int policy);

DESCRIPTION
       sched_get_priority_max returns the maximum priority value that can  be
       used   with   the   scheduling	algorithm   identified	 by   policy.
       sched_get_priority_min returns the minimum priority value that can  be
       used  with  the	scheduling  algorithm identified by policy. Supported
       policy values are SCHED_FIFO, SCHED_RR, and SCHED_OTHER.

       Processes with numerically higher priority values are scheduled before
       processes  with	numerically  lower  priority  values. Thus, the value
       returned by sched_get_priority_max will	be  greater  than  the	value
       returned by sched_get_priority_min.

       Linux  allows  the  static priority value range 1 to 99 for SCHED_FIFO
       and SCHED_RR and the priority 0 for SCHED_OTHER.	 Scheduling  priority
       ranges for the various policies are not alterable.

       The  range  of  scheduling priorities may vary on other POSIX systems,
       thus it is a good idea for portable applications to use a virtual pri-
       ority range and map it to the interval given by sched_get_priority_max
       and sched_get_priority_min.  POSIX.1b requires a spread of at least 32
       between	the  maximum  and  the	minimum	 values	 for  SCHED_FIFO  and
       SCHED_RR.

       POSIX systems on	 which	sched_get_priority_max	and  sched_get_prior-
       ity_min are available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>.


RETURN VALUE
       On success, sched_get_priority_max and  sched_get_priority_min  return
       the  maximum/minimum  priority  value for the named scheduling policy.
       On error, -1 is returned, errno is set appropriately.

ERRORS
       EINVAL The parameter policy does not  identify  a  defined  scheduling
	      policy.

CONFORMING TO
       POSIX.1b (formerly POSIX.4)

SEE ALSO
       sched_setaffinity(2),   sched_getaffinity(2),   sched_setscheduler(2),
       sched_getscheduler(2), sched_setparam(2), sched_getparam(2)

       sched_setscheduler(2)  has  a  description  of  the  Linux  scheduling
       scheme.

       Programming  for	 the  real  world  -  POSIX.4 by Bill O. Gallmeister,
       O’Reilly & Associates, Inc., ISBN 1-56592-074-0
       IEEE Std 1003.1b-1993 (POSIX.1b standard)
       ISO/IEC 9945-1:1996



Linux 1.3.81			  1996-04-10		  GET_PRIORITY_MAX(2)