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, 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 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, POSIX.1-2008.

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 5.10 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
       https://www.kernel.org/doc/man-pages/.

Linux                                              2017-09-15                          SCHED_GET_PRIORITY_MAX(2)