PTHREAD_SETSCHEDPRIO(3)    POSIX Programmer's Manual   PTHREAD_SETSCHEDPRIO(3)



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

NAME
       pthread_setschedprio -- dynamic thread scheduling parameters access
       (REALTIME THREADS)

SYNOPSIS
       #include <pthread.h>

       int pthread_setschedprio(pthread_t thread, int prio);

DESCRIPTION
       The pthread__setschedprio() function shall set the scheduling priority
       for the thread whose thread ID is given by thread to the value given by
       prio.  See Scheduling Policies for a description on how this function
       call affects the ordering of the thread in the thread list for its new
       priority.

       If the pthread__setschedprio() function fails, the scheduling priority
       of the target thread shall not be changed.

RETURN VALUE
       If successful, the pthread__setschedprio() function shall return zero;
       otherwise, an error number shall be returned to indicate the error.

ERRORS
       The pthread__setschedprio() function may fail if:

       EINVAL The value of prio is invalid for the scheduling policy of the
              specified thread.

       EPERM  The caller does not have appropriate privileges to set the
              scheduling priority of the specified thread.

       The pthread__setschedprio() function shall not return an error code of
       [EINTR].

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       The pthread__setschedprio() function provides a way for an application
       to temporarily raise its priority and then lower it again, without
       having the undesired side-effect of yielding to other threads of the
       same priority. This is necessary if the application is to implement its
       own strategies for bounding priority inversion, such as priority
       inheritance or priority ceilings. This capability is especially
       important if the implementation does not support the Thread Priority
       Protection or Thread Priority Inheritance options, but even if those
       options are supported it is needed if the application is to bound
       priority inheritance for other resources, such as semaphores.

       The standard developers considered that while it might be preferable
       conceptually to solve this problem by modifying the specification of
       pthread__setschedparam(), it was too late to make such a change, as
       there may be implementations that would need to be changed. Therefore,
       this new function was introduced.

       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
       None.

SEE ALSO
       Scheduling Policies, pthread__getschedparam()

       The Base Definitions volume of POSIX.1-2017, <pthread.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  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.opengroup.org/unix/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                  2017              PTHREAD_SETSCHEDPRIO(3)
