trusty (2) sched_get_priority_min.2.gz

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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/.