NAME
sched_setparam, sched_getparam - set and get scheduling
parameters
SYNOPSIS
#include <sched.h>
int sched_setparam(pid_t pid, const struct sched_param *p);
int sched_getparam(pid_t pid, struct sched_param *p);
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 current pro-
cess are set. The interpretation of the parameter p depends
on the selected policy. Currently, the following three
scheduling policies are supported under Linux: SCHED_FIFO,
SCHED_RR, and SCHED_OTHER.
sched_getparam retrieves the scheduling parameters for the
process identified by pid. If pid is zero, then the parame-
ters of the current process are retrieved.
sched_setparam checks the validity of p for the scheduling
policy of the process. The parameter p->sched_priority must
lie within the range given by sched_get_priority_min and
sched_get_priority_max.
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, errno is set appropriately.
ERRORS
ESRCH The process whose ID is pid could not be found.
EPERM The calling process does not have appropriate
privileges. The process calling sched_setparam needs
an effective uid equal to the euid or uid of the
process identified by pid, or it must be a superuser
process.
EINVAL The parameter p does not make sense for the current
scheduling policy.
CONFORMING TO
POSIX.1b (formerly POSIX.4)
SEE ALSO
sched_setscheduler(2), sched_getscheduler(2),
sched_get_priority_max(2), sched_get_priority_min(2),
nice(2), setpriority(2), getpriority(2),
sched_setscheduler(2) has a description of the Linux
scheduling scheme.
Programming for the real world - by Bill O. Gallmeister,
O'Reilly & Associates, Inc., ISBN 1-56592-074-0
IEEE Std 1003.1b-1993 (POSIX.1b standard)
ISO/IEC 9945-1:1996