.\"
.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for
.\" permission to reproduce portions of its copyrighted documentation.
.\" Original documentation from The Open Group can be obtained online at
.\" http://www.opengroup.org/bookstore/.
.\"
.\" The Institute of Electrical and Electronics Engineers and The Open
.\" Group, have given us permission to reprint portions of their
.\" documentation.
.\"
.\" In the following statement, the phrase ``this text'' refers to portions
.\" of the system documentation.
.\"
.\" Portions of this text are reprinted and reproduced in electronic form
.\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
.\" Standard for Information Technology -- Portable Operating System
.\" Interface (POSIX), The Open Group Base Specifications Issue 6,
.\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
.\" Engineers, Inc and The Open Group.  In the event of any discrepancy
.\" between these versions 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.
.\"
.\" This notice shall appear on any product containing this material.
.\"
.\" The contents of this file are subject to the terms of the
.\" Common Development and Distribution License (the "License").
.\" You may not use this file except in compliance with the License.
.\"
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
.\" or http://www.opensolaris.org/os/licensing.
.\" See the License for the specific language governing permissions
.\" and limitations under the License.
.\"
.\" When distributing Covered Code, include this CDDL HEADER in each
.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
.\" If applicable, add the following below this CDDL HEADER, with the
.\" fields enclosed by brackets "[]" replaced with your own identifying
.\" information: Portions Copyright [yyyy] [name of copyright owner]
.\"
.\"
.\" Copyright (c) 1992, X/Open Company Limited  All Rights Reserved
.\" Portions Copyright (c) 2008, Sun Microsystems, Inc.  All Rights Reserved.
.\"
.TH SCHED.H 3HEAD "Apr 1, 2008"
.SH NAME
sched.h, sched \- execution scheduling
.SH SYNOPSIS
.LP
.nf
\fB#include <sched.h>\fR
.fi

.SH DESCRIPTION
.sp
.LP
The <\fBsched.h\fR> header defines the \fBsched_param\fR structure, which
contains the scheduling parameters required for implementation of each
supported scheduling policy. This structure contains the following member:
.sp
.in +2
.nf
int    sched_priority    process execution scheduling priority
.fi
.in -2

.sp
.LP
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.
.sp
.LP
The scheduling policies are indicated by the values of the following symbolic
constants:
.sp
.ne 2
.na
\fB\fBSCHED_OTHER\fR\fR
.ad
.RS 15n
Processes are scheduled according to the traditional Time-Sharing Class (TS)
policy as described in \fBpriocntl\fR(2).
.RE

.sp
.ne 2
.na
\fB\fBSCHED_FIFO\fR\fR
.ad
.RS 15n
Processes are scheduled in the Real-Time (RT) scheduling class, according to
the First-In-First-Out  (FIFO) policy. Processes scheduled to this policy, if
not preempted by a higher priority or interrupted by a signal, will proceed
until completion.
.RE

.sp
.ne 2
.na
\fB\fBSCHED_RR\fR\fR
.ad
.RS 15n
Processes are scheduled in the Real-Time (RT) scheduling class, according to
the Round-Robin (RR) policy. Processes scheduled to this policy, if not
preempted by a higher priority or interrupted by a signal, will execute for a
time period, returned by \fBsched_rr_get_interval\fR(3C) or by the system.
.RE

.sp
.ne 2
.na
\fB\fBSCHED_IA\fR\fR
.ad
.RS 15n
Processes are scheduled according to the Inter-Active Class (IA) policy as
described in \fBpriocntl\fR(2).
.RE

.sp
.ne 2
.na
\fB\fBSCHED_FSS\fR\fR
.ad
.RS 15n
Processes are scheduled according to the Fair-Share Class (FSS) policy as
described in \fBpriocntl\fR(2).
.RE

.sp
.ne 2
.na
\fB\fBSCHED_FX\fR\fR
.ad
.RS 15n
Processes are scheduled according to the Fixed-Priority Class (FX) policy as
described in \fBpriocntl\fR(2).
.RE

.sp
.LP
The values of these constants are distinct.
.sp
.LP
Inclusion of the \fB<sched.h>\fR header will make visible symbols defined in
the header \fB<time.h>\fR.
.SH SEE ALSO
.sp
.LP
.BR priocntl (2),
.BR sched_get_priority_max (3C),
.BR sched_get_priority_min (3C),
.BR sched_rr_get_interval (3C),
.BR time.h (3HEAD)