PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

PTHREAD_GETSCHEDPARAM(3P) POSIX Programmer's ManualPTHREAD_GETSCHEDPARAM(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

       pthread_getschedparam, pthread_setschedparam — dynamic thread
       scheduling parameters access (REALTIME THREADS)

SYNOPSIS         top

       #include <pthread.h>

       int pthread_getschedparam(pthread_t thread, int *restrict policy,
           struct sched_param *restrict param);
       int pthread_setschedparam(pthread_t thread, int policy,
           const struct sched_param *param);

DESCRIPTION         top

       The pthread_getschedparam() and pthread_setschedparam() functions
       shall, respectively, get and set the scheduling policy and parameters
       of individual threads within a multi-threaded process to be retrieved
       and set. For SCHED_FIFO and SCHED_RR, the only required member of the
       sched_param structure is the priority sched_priority.  For
       SCHED_OTHER, the affected scheduling parameters are implementation-
       defined.

       The pthread_getschedparam() function shall retrieve the scheduling
       policy and scheduling parameters for the thread whose thread ID is
       given by thread and shall store those values in policy and param,
       respectively. The priority value returned from
       pthread_getschedparam() shall be the value specified by the most
       recent pthread_setschedparam(), pthread_setschedprio(), or
       pthread_create() call affecting the target thread. It shall not
       reflect any temporary adjustments to its priority as a result of any
       priority inheritance or ceiling functions. The
       pthread_setschedparam() function shall set the scheduling policy and
       associated scheduling parameters for the thread whose thread ID is
       given by thread to the policy and associated parameters provided in
       policy and param, respectively.

       The policy parameter may have the value SCHED_OTHER, SCHED_FIFO, or
       SCHED_RR. The scheduling parameters for the SCHED_OTHER policy are
       implementation-defined. The SCHED_FIFO and SCHED_RR policies shall
       have a single scheduling parameter, priority.

       If _POSIX_THREAD_SPORADIC_SERVER is defined, then the policy argument
       may have the value SCHED_SPORADIC, with the exception for the
       pthread_setschedparam() function that if the scheduling policy was
       not SCHED_SPORADIC at the time of the call, it is implementation-
       defined whether the function is supported; in other words, the
       implementation need not allow the application to dynamically change
       the scheduling policy to SCHED_SPORADIC. The sporadic server
       scheduling policy has the associated parameters
       sched_ss_low_priority, sched_ss_repl_period, sched_ss_init_budget,
       sched_priority, and sched_ss_max_repl.  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.

       If the pthread_setschedparam() function fails, the scheduling
       parameters shall not be changed for the target thread.

RETURN VALUE         top

       If successful, the pthread_getschedparam() and
       pthread_setschedparam() functions shall return zero; otherwise, an
       error number shall be returned to indicate the error.

ERRORS         top

       The pthread_setschedparam() function shall fail if:

       ENOTSUP
              An attempt was made to set the policy or scheduling parameters
              to an unsupported value.

       ENOTSUP
              An attempt was made to dynamically change the scheduling
              policy to SCHED_SPORADIC, and the implementation does not
              support this change.

       The pthread_setschedparam() function may fail if:

       EINVAL The value specified by policy or one of the scheduling
              parameters associated with the scheduling policy policy is
              invalid.

       EPERM  The caller does not have appropriate privileges to set either
              the scheduling parameters or the scheduling policy of the
              specified thread.

       EPERM  The implementation does not allow the application to modify
              one of the parameters to the value specified.

       These functions shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       If an implementation detects use of a thread ID after the end of its
       lifetime, it is recommended that the function should fail and report
       an [ESRCH] error.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       pthread_setschedprio(3p), sched_getparam(3p), sched_getscheduler(3p)

       The Base Definitions volume of POSIX.1‐2008, pthread.h(0p),
       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 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.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013           PTHREAD_GETSCHEDPARAM(3P)

Pages that refer to this page: pthread.h(0p)pthread_setschedparam(3p)pthread_setschedprio(3p)