sched.h

<sched.h>(P)							 <sched.h>(P)



NAME
       sched.h - execution scheduling (REALTIME)

SYNOPSIS
       #include <sched.h>

DESCRIPTION
       The  <sched.h>  header  shall  define the sched_param structure, which
       contains the scheduling parameters required for implementation of each
       supported scheduling policy. This structure shall contain at least the
       following member:


	      int	sched_priority	      Process execution scheduling priority.

       In   addition,	if   _POSIX_SPORADIC_SERVER   or   _POSIX_THREAD_SPO-
       RADIC_SERVER   is   defined,  the  sched_param  structure  defined  in
       <sched.h> shall contain the following members  in  addition  to	those
       specified above:


	      int	      sched_ss_low_priority Low scheduling priority for
						    sporadic server.
	      struct timespec sched_ss_repl_period  Replenishment period for
						    sporadic server.
	      struct timespec sched_ss_init_budget  Initial budget for sporadic server.
	      int	      sched_ss_max_repl	    Maximum pending replenishments for
						    sporadic server.

       Each process is controlled by an associated scheduling policy and pri-
       ority. Associated with each policy is a priority range.	 Each  policy
       definition  specifies  the minimum priority range for that policy. The
       priority ranges for each policy may overlap  the	 priority  ranges  of
       other policies.

       Four  scheduling	 policies  are	defined; others may be defined by the
       implementation. The four standard policies are indicated by the values
       of the following symbolic constants:

       SCHED_FIFO
	      First in-first out (FIFO) scheduling policy.

       SCHED_RR
	      Round robin scheduling policy.

       SCHED_SPORADIC
	      Sporadic server scheduling policy.

       SCHED_OTHER
	      Another scheduling policy.


       The values of these constants are distinct.

       The  following  shall be declared as functions and may also be defined
       as macros. Function prototypes shall be provided.


	      int    sched_get_priority_max(int);
	      int    sched_get_priority_min(int);

	      int    sched_getparam(pid_t, struct sched_param *);
	      int    sched_getscheduler(pid_t);

	      int    sched_rr_get_interval(pid_t, struct timespec *);

	      int    sched_setparam(pid_t, const struct sched_param *);
	      int    sched_setscheduler(pid_t, int, const struct sched_param *);

	      int    sched_yield(void);



       Inclusion of the <sched.h> header may make visible  all	symbols	 from
       the <time.h> header.

       The following sections are informative.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       <time.h>

COPYRIGHT
       Portions	 of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information  Technol-
       ogy  --	Portable  Operating  System Interface (POSIX), The Open Group
       Base Specifications Issue 6, Copyright (C) 2001-2003 by the  Institute
       of  Electrical  and  Electronics Engineers, Inc and The Open Group. In
       the event of any discrepancy between this  version  and	the  original
       IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard is  the	 referee  document.  The  original  Standard  can  be
       obtained online at http://www.opengroup.org/unix/online.html .



POSIX				     2003			 <sched.h>(P)