This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
The <sched.h> header shall define the pid_t type as described in
The <sched.h> header shall define the time_t type as described in
The <sched.h> header shall define the timespec structure as described
The <sched.h> header shall define the sched_param structure, which
shall include the scheduling parameters required for implementation
of each supported scheduling policy. This structure shall include at
least the following member:
int sched_priority Process or thread execution scheduling priority.
The sched_param structure defined in <sched.h> shall include the
following members in addition to those specified above:
int sched_ss_low_priority Low scheduling priority for
struct timespec sched_ss_repl_period Replenishment period for
struct timespec sched_ss_init_budget Initial budget for sporadic server.
int sched_ss_max_repl Maximum pending replenishments for
Each process or thread 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.
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.
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 sched.h(0P)