SCHED_SETPARAM(3P)        POSIX Programmer's Manual       SCHED_SETPARAM(3P)

PROLOG         top

       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         top

       sched_setparam — set scheduling parameters (REALTIME)

SYNOPSIS         top

       #include <sched.h>

       int sched_setparam(pid_t pid, const struct sched_param *param);

DESCRIPTION         top

       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 specified 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

       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
       kernel-scheduled entities used by the process contention scope

RETURN VALUE         top

       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         top

       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

       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

       The following sections are informative.

EXAMPLES         top




RATIONALE         top




SEE ALSO         top

       Scheduling Policies, sched_getparam(3p), sched_getscheduler(3p),

       The Base Definitions volume of POSIX.1‐2008, sched.h(0p)

COPYRIGHT         top

       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 .

       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_SETPARAM(3P)