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_attr_getschedpolicy,  pthread_attr_setschedpolicy  —  get  and set the schedpolicy
       attribute (REALTIME THREADS)

SYNOPSIS

       #include <pthread.h>

       int pthread_attr_getschedpolicy(const pthread_attr_t *restrict attr,
           int *restrict policy);
       int pthread_attr_setschedpolicy(pthread_attr_t *attr, int policy);

DESCRIPTION

       The    pthread_attr_getschedpolicy()    and    pthread_attr_setschedpolicy()    functions,
       respectively, shall get and set the schedpolicy attribute in the attr argument.

       The  supported values of policy shall include SCHED_FIFO, SCHED_RR, and SCHED_OTHER, which
       are defined in the <sched.h> header. When threads executing  with  the  scheduling  policy
       SCHED_FIFO,  SCHED_RR,  or  SCHED_SPORADIC  are waiting on a mutex, they shall acquire the
       mutex in priority order when the mutex is unlocked.

       The  behavior  is  undefined  if  the  value   specified   by   the   attr   argument   to
       pthread_attr_getschedpolicy()  or  pthread_attr_setschedpolicy()  does  not  refer  to  an
       initialized thread attributes object.

RETURN VALUE

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

ERRORS

       The pthread_attr_setschedpolicy() function shall fail if:

       ENOTSUP
              An attempt was made to set the attribute to an unsupported value.

       The pthread_attr_setschedpolicy() function may fail if:

       EINVAL The value of policy is not valid.

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

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       After these attributes have  been  set,  a  thread  can  be  created  with  the  specified
       attributes  using  pthread_create().   Using  these  routines  does not affect the current
       running thread.

       See Section 2.9.4, Thread Scheduling for further details on thread  scheduling  attributes
       and their default settings.

RATIONALE

       If   an  implementation  detects  that  the  value  specified  by  the  attr  argument  to
       pthread_attr_getschedpolicy()  or  pthread_attr_setschedpolicy()  does  not  refer  to  an
       initialized  thread attributes object, it is recommended that the function should fail and
       report an [EINVAL] error.

FUTURE DIRECTIONS

       None.

SEE ALSO

       pthread_attr_destroy(), pthread_attr_getscope(), pthread_attr_getinheritsched(),
       pthread_attr_getschedparam(), pthread_create()

       The Base Definitions volume of POSIX.1‐2008, <pthread.h>, <sched.h>

COPYRIGHT

       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 .