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);
DESCRIPTIONsched_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 pri‐
ority range and map it to the interval given by sched_get_prior‐
ity_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_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, POSIX.1-2008.
SEE ALSOsched_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 4.14 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)
