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 iden-
       tified 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_SCHED-
       ULING 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_setsched-
       uler(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 3.25 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/.



Linux                                                      2006-03-23                                  SCHED_GET_PRIORITY_MAX(2)