1SCHED_SETPARAM(3P)         POSIX Programmer's Manual        SCHED_SETPARAM(3P)
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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.
10

NAME

12       sched_setparam — set scheduling parameters (REALTIME)
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SYNOPSIS

15       #include <sched.h>
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17       int sched_setparam(pid_t pid, const struct sched_param *param);
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DESCRIPTION

20       The sched_setparam() function shall set the  scheduling  parameters  of
21       the process specified by pid to the values specified by the sched_param
22       structure pointed to by param.  The value of the sched_priority  member
23       in  the sched_param structure shall be any integer within the inclusive
24       priority range for the current scheduling policy of the process  speci‐
25       fied by pid.  Higher numerical values for the priority represent higher
26       priorities.  If the value of pid  is  negative,  the  behavior  of  the
27       sched_setparam() function is unspecified.
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29       If  a  process  specified by pid exists, and if the calling process has
30       permission, the scheduling parameters shall  be  set  for  the  process
31       whose process ID is equal to pid.
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33       If  pid is zero, the scheduling parameters shall be set for the calling
34       process.
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36       The conditions under which one process has  permission  to  change  the
37       scheduling parameters of another process are implementation-defined.
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39       Implementations  may require the requesting process to have appropriate
40       privileges to set its own scheduling parameters  or  those  of  another
41       process.
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43       See  Scheduling Policies for a description on how this function affects
44       the scheduling of the threads within the target process.
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46       If the  current  scheduling  policy  for  the  target  process  is  not
47       SCHED_FIFO,  SCHED_RR, or SCHED_SPORADIC, the result is implementation-
48       defined; this case includes the SCHED_OTHER policy.
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50       The specified sched_ss_repl_period shall be greater than  or  equal  to
51       the  specified  sched_ss_init_budget for the function to succeed; if it
52       is not, then the function shall fail.
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54       The value of sched_ss_max_repl shall  be  within  the  inclusive  range
55       [1,{SS_REPL_MAX}]  for  the  function  to succeed; if not, the function
56       shall fail. It is  unspecified  whether  the  sched_ss_repl_period  and
57       sched_ss_init_budget  values are stored as provided by this function or
58       are rounded to align with the resolution of the clock being used.
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60       This function is not atomic  with  respect  to  other  threads  in  the
61       process. Threads may continue to execute while this function call is in
62       the process of changing the scheduling policy for the  underlying  ker‐
63       nel-scheduled entities used by the process contention scope threads.
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RETURN VALUE

66       If successful, the sched_setparam() function shall return zero.
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68       If  the  call  to  sched_setparam() is unsuccessful, the priority shall
69       remain unchanged, and the function shall return a value of -1  and  set
70       errno to indicate the error.
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ERRORS

73       The sched_setparam() function shall fail if:
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75       EINVAL One  or  more  of the requested scheduling parameters is outside
76              the range defined for the scheduling  policy  of  the  specified
77              pid.
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79       EPERM  The  requesting  process  does  not  have  permission to set the
80              scheduling parameters for the specified  process,  or  does  not
81              have appropriate privileges to invoke sched_setparam().
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83       ESRCH  No process can be found corresponding to that specified by pid.
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85       The following sections are informative.
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EXAMPLES

88       None.
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APPLICATION USAGE

91       None.
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RATIONALE

94       None.
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FUTURE DIRECTIONS

97       None.
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SEE ALSO

100       Scheduling     Policies,     sched_getparam(),    sched_getscheduler(),
101       sched_setscheduler()
102
103       The Base Definitions volume of POSIX.1‐2017, <sched.h>
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106       Portions of this text are reprinted and reproduced in  electronic  form
107       from  IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
108       table Operating System Interface (POSIX), The Open Group Base  Specifi‐
109       cations  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of
110       Electrical and Electronics Engineers, Inc and The Open Group.   In  the
111       event of any discrepancy between this version and the original IEEE and
112       The Open Group Standard, the original IEEE and The Open Group  Standard
113       is  the  referee document. The original Standard can be obtained online
114       at http://www.opengroup.org/unix/online.html .
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116       Any typographical or formatting errors that appear  in  this  page  are
117       most likely to have been introduced during the conversion of the source
118       files to man page format. To report such errors,  see  https://www.ker
119       nel.org/doc/man-pages/reporting_bugs.html .
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123IEEE/The Open Group                  2017                   SCHED_SETPARAM(3P)
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