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, SCHED_OTHER, and  SCHED_BATCH.   Further
       details about these policies can be found in sched_setscheduler(2).

       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 and SCHED_BATCH.  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 priority range and map it to the interval given
       by  sched_get_priority_max() and sched_get_priority_min().  POSIX.1-2001 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_priority_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,
       and errno is set appropriately.

ERRORS

       EINVAL The argument policy does not identify a defined scheduling policy.

CONFORMING TO

       POSIX.1-2001.

SEE ALSO

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

       Programming for the real world - POSIX.4 by Bill O. Gallmeister, O'Reilly & Associates,
       Inc., ISBN 1-56592-074-0.

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A description of the
       project, and information about reporting bugs, can be found at
       http://www.kernel.org/doc/man-pages/.