NAME¶
sched_setparam, sched_getparam - set and get scheduling parameters
SYNOPSIS¶
#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;
...
};
DESCRIPTION¶
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(7) 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 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>.
RETURN VALUE¶
On success,
sched_setparam() and
sched_getparam() return 0. On
error, -1 is returned, and
errno is set appropriately.
ERRORS¶
- 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 calling process does not have appropriate
privileges (Linux: does not have the CAP_SYS_NICE capability).
- ESRCH
- The process whose ID is pid could not be found.
POSIX.1-2001, POSIX.1-2008.
NOTES¶
Scheduling parameters are in fact per-thread attributes on Linux; see
sched(7).
SEE ALSO¶
getpriority(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)
COLOPHON¶
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