FreeBSD manual
download PDF document: sched_get_priority_max.2.pdf
SCHED_GET_PRIORITY_MAX(2) FreeBSD System Calls Manual
NAME
sched_get_priority_max, sched_get_priority_min, sched_rr_get_interval -
get scheduling parameter limits
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sched.h>
int
sched_get_priority_max(int policy);
int
sched_get_priority_min(int policy);
int
sched_rr_get_interval(pid_t pid, struct timespec *interval);
DESCRIPTION
The sched_get_priority_max() and sched_get_priority_min() system calls
return the appropriate maximum or minimum, respectively, for the
scheduling policy specified by policy. The sched_rr_get_interval()
system call updates the timespec structure referenced by the interval
argument to contain the current execution time limit (i.e., time quantum)
for the process specified by pid. If pid is zero, the current execution
time limit for the calling process is returned.
The value of policy should be one of the scheduling policy values defined
in <sched.h>:
[SCHED_FIFO] First-in-first-out fixed priority scheduling with no round
robin scheduling;
[SCHED_OTHER] The standard time sharing scheduler;
[SCHED_RR] Round-robin scheduling across same priority processes.
RETURN VALUES
If successful, the sched_get_priority_max() and sched_get_priority_min()
system calls shall return the appropriate maximum or minimum values,
respectively. If unsuccessful, they shall return a value of -1 and set
errno to indicate the error.
The sched_rr_get_interval() function returns the value 0 if successful;
otherwise the value -1 is returned and the global variable errno is set
to indicate the error.
ERRORS
On failure errno will be set to the corresponding value:
[EINVAL] The value of the policy argument does not represent a
defined scheduling policy.
[ENOSYS] The sched_get_priority_max(),
sched_get_priority_min(), and sched_rr_get_interval()
system calls are not supported by the implementation.
STANDARDS
The sched_get_priority_max(), sched_get_priority_min(), and
sched_rr_get_interval() system calls conform to IEEE Std 1003.1b-1993
("POSIX.1b").
FreeBSD 14.0-RELEASE-p11 March 12, 1998 FreeBSD 14.0-RELEASE-p11