NAME
sched_get_priority_max,
sched_get_priority_min,
sched_rr_get_interval —
get scheduling parameter
limits
LIBRARY
library “libc”
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
Thesched_get_priority_max()
and
sched_get_priority_min()
functions return the appropriate maximum or minimum, respectively, for the
scheduling policy specified by policy. The
sched_rr_get_interval()
function 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() functions 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 parameter does not represent a defined scheduling policy.
- [
ENOSYS] - The
sched_get_priority_max(),sched_get_priority_min(), andsched_rr_get_interval() functions are not supported by the implementation. - [
ESRCH] - No process can be found corresponding to that specified by pid.
SEE ALSO
sched_getparam(2), sched_getscheduler(2), sched_setparam(2), sched_setscheduler(2)
STANDARDS
The sched_setscheduler() and
sched_getscheduler() functions conform to
IEEE Std 1003.1b-1993
(“POSIX.1b”).