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 thread whose thread ID is specified in
pid.
If
pid is zero, then the parameters of the calling thread are set. The
interpretation of the argument
param depends on the scheduling policy
of the thread identified by
pid. See
sched(7) for a description
of the scheduling policies supported under Linux.
sched_getparam() retrieves the scheduling parameters for the thread
identified by
pid. If
pid is zero, then the parameters of the
calling thread are retrieved.
sched_setparam() checks the validity of
param for the scheduling
policy of the thread. 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(7).
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.
- EINVAL
- Invalid arguments: param is NULL or pid is negative
- EINVAL
- (sched_setparam()) The argument param does not make sense
for the current scheduling policy.
- EPERM
- (sched_setparam()) The caller does not have appropriate privileges
(Linux: does not have the CAP_SYS_NICE capability).
- ESRCH
- The thread whose ID is pid could not be found.
POSIX.1-2001, POSIX.1-2008.
getpriority(2),
gettid(2),
nice(2),
sched_get_priority_max(2),
sched_get_priority_min(2),
sched_getaffinity(2),
sched_getscheduler(2),
sched_setaffinity(2),
sched_setattr(2),
sched_setscheduler(2),
setpriority(2),
capabilities(7),
sched(7)