sched_setparam, sched_getparam — set and get scheduling parameters
#include <sched.h>
int sched_setparam( |
pid_t pid, |
const struct sched_param *param); |
int sched_getparam( |
pid_t pid, |
struct sched_param *param); |
struct sched_param {
...
int sched_priority;
...
};
sched_setparam() sets the
scheduling parameters associated with the scheduling policy
for the process identified by pid. If pid is zero, then the
parameters of the calling process are set. The interpretation
of the argument param
depends on the scheduling policy of the process identified by
pid. See sched_setscheduler(2) for a
description of the scheduling policies supported under
Linux.
sched_getparam() retrieves
the scheduling parameters for the process identified by
pid. If pid is zero, then the
parameters of the calling process are retrieved.
sched_setparam() checks the
validity of param for
the scheduling policy of the process. The value param−>sched_priority
must lie within the range given by sched_get_priority_min(2)
and sched_get_priority_max(2).
For a discussion of the privileges and resource limits related to scheduling priority and policy, see sched_setscheduler(2).
POSIX systems on which sched_setparam() and sched_getparam() are available define
_POSIX_PRIORITY_SCHEDULING in
<unistd.h>
On success, sched_setparam()
and sched_getparam() return 0.
On error, −1 is returned, and errno is set appropriately.
The argument param does not make sense
for the current scheduling policy.
The calling process does not have appropriate
privileges (Linux: does not have the CAP_SYS_NICE capability).
The process whose ID is pid could not be
found.
getpriority(2), nice(2), sched_get_priority_max(2), sched_get_priority_min(2), sched_getaffinity(2), sched_getscheduler(2), sched_setaffinity(2), sched_setscheduler(2), setpriority(2), capabilities(7)
Programming for the real world − POSIX.4 by Bill O. Gallmeister, O'Reilly & Associates, Inc., ISBN 1-56592-074-0