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.  Supported
       policy values are SCHED_FIFO, SCHED_RR, SCHED_OTHER, and SCHED_BATCH.  Further details about these policies can be found in sched_setsched-
       uler(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  pri-
       ority  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  pol-
       icy.  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 3.27 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)