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

       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(3POSIX)