ing parameters access (REALTIME THREADS)

SYNOPSIS
       #include <pthread.h>

       int pthread_getschedparam(pthread_t thread, int *restrict policy,
              struct sched_param *restrict param);
       int pthread_setschedparam(pthread_t thread, int policy,
              const struct sched_param *param);


DESCRIPTION
       The  pthread_getschedparam()  and   pthread_setschedparam()   functions
       shall,  respectively,  get and set the scheduling policy and parameters
       of individual threads within a multi-threaded process to  be  retrieved
       and  set.  For SCHED_FIFO and SCHED_RR, the only required member of the
       sched_param structure is the priority sched_priority. For  SCHED_OTHER,
       the affected scheduling parameters are implementation-defined.

       The pthread_getschedparam() function shall retrieve the scheduling pol-
       icy and scheduling parameters for the thread whose thread ID  is  given
       by  thread  and  shall  store those values in policy and param, respec-
       tively. The priority value returned from pthread_getschedparam()  shall
       be  the  value  specified  by  the most recent pthread_setschedparam(),
       pthread_setschedprio(), or pthread_create() call affecting  the  target
       thread.  It shall not reflect any temporary adjustments to its priority
       as a result of any  priority  inheritance  or  ceiling  functions.  The
       pthread_setschedparam()  function  shall  set the scheduling policy and
       associated scheduling parameters for the  thread  whose  thread  ID  is
       given  by  thread  to  the policy and associated parameters provided in
       policy and param, respectively.

       The policy parameter may have the  value  SCHED_OTHER,  SCHED_FIFO,  or
       SCHED_RR.  The  scheduling  parameters  for  the SCHED_OTHER policy are
       implementation-defined. The SCHED_FIFO and SCHED_RR policies shall have
       a single scheduling parameter, priority.

       If  _POSIX_THREAD_SPORADIC_SERVER  is defined, then the policy argument
       may  have  the  value  SCHED_SPORADIC,  with  the  exception  for   the
       pthread_setschedparam()  function that if the scheduling policy was not
       SCHED_SPORADIC at the time of the call,  it  is  implementation-defined
       whether  the  function is supported; in other words, the implementation
       need not allow the application to  dynamically  change  the  scheduling
       policy to SCHED_SPORADIC. The sporadic server scheduling policy has the
       associated  parameters   sched_ss_low_priority,   sched_ss_repl_period,
       sched_ss_init_budget, sched_priority, and sched_ss_max_repl. The speci-
       fied sched_ss_repl_period shall be greater than or equal to the  speci-
       fied  sched_ss_init_budget  for  the function to succeed; if it is not,
       then the function shall fail. The value of sched_ss_max_repl  shall  be
       within  the inclusive range [1, {SS_REPL_MAX}] for the function to suc-
       ceed; if not, the function shall fail.

       If the pthread_setschedparam() function fails, the  scheduling  parame-
       ters shall not be changed for the target thread.

       The pthread_setschedparam() function may fail if:

       EINVAL The value specified by policy or one of the  scheduling  parame-
              ters associated with the scheduling policy policy is invalid.

       ENOTSUP
              An  attempt  was made to set the policy or scheduling parameters
              to an unsupported value.

       ENOTSUP
              An attempt was made to dynamically change the scheduling  policy
              to  SCHED_SPORADIC, and the implementation does not support this
              change.

       EPERM  The caller does not  have  the  appropriate  permission  to  set
              either the scheduling parameters or the scheduling policy of the
              specified thread.

       EPERM  The implementation does not allow the application to modify  one
              of the parameters to the value specified.

       ESRCH  The  value  specified  by  thread  does  not refer to a existing
              thread.


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

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread_setschedprio() , sched_getparam() , sched_getscheduler() ,  the
       Base Definitions volume of IEEE Std 1003.1-2001, <pthread.h>, <sched.h>

COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  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