SCHED_GET_PRIORITY_MAX(2)           Linux Programmer's Manual           SCHED_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.  Sup‐
       ported policy values are SCHED_FIFO, SCHED_RR, SCHED_OTHER, SCHED_BATCH,  SCHED_IDLE,  and
       SCHED_DEADLINE.  Further details about these policies can be found in sched(7).

       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 range 1 to 99 for the SCHED_FIFO and SCHED_RR policies,
       and the priority 0 for the remaining policies.  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/mini‐
       mum 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), sched(7)

COLOPHON
       This page is part of release 3.74 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



Linux                                       2014-05-12                  SCHED_GET_PRIORITY_MAX(2)