1sched.h(0P)                POSIX Programmer's Manual               sched.h(0P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

12       sched.h — execution scheduling
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SYNOPSIS

15       #include <sched.h>
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DESCRIPTION

18       The <sched.h> header shall  define  the  pid_t  type  as  described  in
19       <sys/types.h>.
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21       The  <sched.h>  header  shall  define  the  time_t type as described in
22       <sys/types.h>.
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24       The <sched.h> header shall define the timespec structure  as  described
25       in <time.h>.
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27       The  <sched.h>  header  shall  define  the sched_param structure, which
28       shall include the scheduling parameters required for implementation  of
29       each supported scheduling policy. This structure shall include at least
30       the following member:
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33           int       sched_priority        Process or thread execution scheduling priority.
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35       The sched_param structure defined in <sched.h> shall include  the  fol‐
36       lowing members in addition to those specified above:
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39           int             sched_ss_low_priority Low scheduling priority for
40                                                 sporadic server.
41           struct timespec sched_ss_repl_period  Replenishment period for
42                                                 sporadic server.
43           struct timespec sched_ss_init_budget  Initial budget for sporadic server.
44           int             sched_ss_max_repl     Maximum pending replenishments for
45                                                 sporadic server.
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47       Each process or thread is controlled by an associated scheduling policy
48       and priority. Associated with each policy is  a  priority  range.  Each
49       policy definition specifies the minimum priority range for that policy.
50       The priority ranges for each policy may overlap the priority ranges  of
51       other policies.
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53       Four  scheduling  policies  are  defined;  others may be defined by the
54       implementation. The four standard policies are indicated by the  values
55       of the following symbolic constants:
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57       SCHED_FIFO    First in-first out (FIFO) scheduling policy.
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59       SCHED_RR      Round robin scheduling policy.
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61       SCHED_SPORADIC
62                     Sporadic server scheduling policy.
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64       SCHED_OTHER   Another scheduling policy.
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66       The values of these constants are distinct.
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68       The following shall be declared as functions and may also be defined as
69       macros. Function prototypes shall be provided.
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72           int    sched_get_priority_max(int);
73           int    sched_get_priority_min(int);
74           int    sched_getparam(pid_t, struct sched_param *);
75           int    sched_getscheduler(pid_t);
76           int    sched_rr_get_interval(pid_t, struct timespec *);
77           int    sched_setparam(pid_t, const struct sched_param *);
78           int    sched_setscheduler(pid_t, int, const struct sched_param *);
79           int    sched_yield(void);
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81       Inclusion of the <sched.h> header may make visible all symbols from the
82       <time.h> header.
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84       The following sections are informative.
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APPLICATION USAGE

87       None.
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RATIONALE

90       None.
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FUTURE DIRECTIONS

93       None.
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SEE ALSO

96       <sys_types.h>, <time.h>
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98       The System Interfaces volume of POSIX.1‐2017, sched_get_priority_max(),
99       sched_getparam(),    sched_getscheduler(),     sched_rr_get_interval(),
100       sched_setparam(), sched_setscheduler(), sched_yield()
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103       Portions  of  this text are reprinted and reproduced in electronic form
104       from IEEE Std 1003.1-2017, Standard for Information Technology --  Por‐
105       table  Operating System Interface (POSIX), The Open Group Base Specifi‐
106       cations Issue 7, 2018 Edition, Copyright (C) 2018 by the  Institute  of
107       Electrical  and  Electronics Engineers, Inc and The Open Group.  In the
108       event of any discrepancy between this version and the original IEEE and
109       The  Open Group Standard, the original IEEE and The Open Group Standard
110       is the referee document. The original Standard can be  obtained  online
111       at http://www.opengroup.org/unix/online.html .
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113       Any  typographical  or  formatting  errors that appear in this page are
114       most likely to have been introduced during the conversion of the source
115       files  to  man page format. To report such errors, see https://www.ker‐
116       nel.org/doc/man-pages/reporting_bugs.html .
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120IEEE/The Open Group                  2017                          sched.h(0P)
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