bionic (3) pthread_setschedprio.3posix.gz

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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.1‐2008, <pthread.h>


       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 .