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.

CONFORMING TO

       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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