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SCHED_SETPARAM(3P)         POSIX Programmer's Manual        SCHED_SETPARAM(3P)
PROLOG
       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.
NAME
       sched_setparam -- set scheduling parameters (REALTIME)
SYNOPSIS
       #include <sched.h>
       int sched_setparam(pid_t pid, const struct sched_param *param);
DESCRIPTION
       The sched_setparam() function shall set the  scheduling  parameters  of
       the process specified by pid to the values specified by the sched_param
       structure pointed to by param.  The value of the sched_priority  member
       in  the sched_param structure shall be any integer within the inclusive
       priority range for the current scheduling policy of the process  speci-
       fied by pid.  Higher numerical values for the priority represent higher
       priorities.  If the value of pid  is  negative,  the  behavior  of  the
       sched_setparam() function is unspecified.
       If  a  process  specified by pid exists, and if the calling process has
       permission, the scheduling parameters shall  be  set  for  the  process
       whose process ID is equal to pid.
       If  pid is zero, the scheduling parameters shall be set for the calling
       process.
       The conditions under which one process has  permission  to  change  the
       scheduling parameters of another process are implementation-defined.
       Implementations  may require the requesting process to have appropriate
       privileges to set its own scheduling parameters  or  those  of  another
       process.
       See  Scheduling Policies for a description on how this function affects
       the scheduling of the threads within the target process.
       If the  current  scheduling  policy  for  the  target  process  is  not
       SCHED_FIFO,  SCHED_RR, or SCHED_SPORADIC, the result is implementation-
       defined; this case includes the SCHED_OTHER policy.
       The specified sched_ss_repl_period shall be greater than  or  equal  to
       the  specified  sched_ss_init_budget for the function to succeed; if it
       is not, then the function shall fail.
       The value of sched_ss_max_repl shall  be  within  the  inclusive  range
       [1,{SS_REPL_MAX}]  for  the  function  to succeed; if not, the function
       shall fail. It is  unspecified  whether  the  sched_ss_repl_period  and
       sched_ss_init_budget  values are stored as provided by this function or
       are rounded to align with the resolution of the clock being used.
       This function is not atomic  with  respect  to  other  threads  in  the
       process. Threads may continue to execute while this function call is in
       the process of changing the scheduling policy for the  underlying  ker-
       nel-scheduled entities used by the process contention scope threads.
RETURN VALUE
       If successful, the sched_setparam() function shall return zero.
       If  the  call  to  sched_setparam() is unsuccessful, the priority shall
       remain unchanged, and the function shall return a value of -1  and  set
       errno to indicate the error.
ERRORS
       The sched_setparam() function shall fail if:
       EINVAL One  or  more  of the requested scheduling parameters is outside
              the range defined for the scheduling  policy  of  the  specified
              pid.
       EPERM  The  requesting  process  does  not  have  permission to set the
              scheduling parameters for the specified  process,  or  does  not
              have appropriate privileges to invoke sched_setparam().
       ESRCH  No process can be found corresponding to that specified by pid.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       None.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       Scheduling     Policies,     sched_getparam(),    sched_getscheduler(),
       sched_setscheduler()
       The Base Definitions volume of POSIX.1-2008, <sched.h>
COPYRIGHT
       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 Electri-
       cal 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 https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                   SCHED_SETPARAM(3P)