sched_get_priority_min

       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.   Schedul-
       ing 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_prior-
       ity_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_prior-
       ity_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  pol-
              icy.

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)
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