<sched.h>(P)						     POSIX Programmer's Manual						      <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_SPORADIC_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 priority. 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 .

IEEE
/The Open Group						       2003							      <sched.h>(P)