NAME    [Toc]    [Back]

       sched_setparam, sched_getparam - set and get scheduling parameters

SYNOPSIS    [Toc]    [Back]

       #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    [Toc]    [Back]

       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 process 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 parameters 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    [Toc]    [Back]

       On  success,  sched_setparam and sched_getparam return 0.  On error, -1
       is returned, errno is set appropriately.

ERRORS    [Toc]    [Back]

       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    [Toc]    [Back]

       POSIX.1b (formerly POSIX.4)

SEE ALSO    [Toc]    [Back]

       sched_setscheduler(2),	  sched_getscheduler(2),      sched_get_prior-
       ity_max(2), sched_get_priority_min(2), nice(2), setpriority(2), getpri-
       ority(2),

       sched_setscheduler(2) has a description of the Linux scheduling scheme.

       Programming  for  the  real  world  -  POSIX.4  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



Linux 1.3.81			  1996-04-10		     SCHED_SETPARAM(2)