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 .