NAME    [Toc]    [Back]

       pthread_setschedparam - Changes a thread's scheduling policy
 and scheduling parameters

SYNOPSIS    [Toc]    [Back]

       #include <pthread.h>

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

LIBRARY    [Toc]    [Back]

       DECthreads POSIX 1003.1c Library (libpthread.so)

STANDARDS    [Toc]    [Back]

       interfaces documented on this reference  page  conform  to
       industry standards as follows:

       IEEE  Std  1003.1c-1995,  POSIX System Application Program
       Interface

PARAMETERS    [Toc]    [Back]

       Thread whose scheduling policy and parameters  are  to  be
       changed.  New scheduling policy value for the thread specified
  in  thread.  The  following   are   valid   values:
       SCHED_BG_NP SCHED_FG_NP SCHED_FIFO SCHED_OTHER SCHED_RR

              See  Guide  to  DECthreads for a description of the
              scheduling policies.  New values of the  scheduling
              parameters  associated  with  the scheduling policy
              for the thread specified in  thread.  Valid  values
              for  the  sched_priority  field  of  a  sched_param
              structure depend on the chosen  scheduling  policy.
              Use the POSIX routines sched_get_priority_min(3) or
              sched_get_priority_max(3) to determine the low  and
              high  limits  of  each  policy.  Additionally, DECthreads
 provides nonportable  priority  range  constants,
   as   follows:   PRI_FIFO_MIN   (low)   to
              PRI_FIFO_MAX (high) PRI_RR_MIN (low) to  PRI_RR_MAX
              (high)  PRI_OTHER_MIN (low) to PRI_OTHER_MAX (high)
              PRI_FG_MIN_NP   (low)   to   PRI_FG_MAX_NP   (high)
              PRI_BG_MIN_NP (low) to PRI_BG_MAX_NP (high)

              The default priority varies by DECthreads platform.
              On Tru64 UNIX, the default  is  19  (that  is,  the
              POSIX  priority of a normal timeshare process).  On
              the non-UNIX platforms, the default priority is the
              midpoint between PRI_FG_MIN_NP and PRI_FG_MAX_NP.

DESCRIPTION    [Toc]    [Back]

       This  routine  changes  both the current scheduling policy
       and associated scheduling parameters of the thread  specified
  by  thread  to  the policy and associated parameters
       provided in policy and param, respectively.

       All currently implemented DECthreads  scheduling  policies
       have  one  scheduling parameter called sched_priority. For
       the policy you choose, you  must  specify  an  appropriate
       value  in  the  sched_priority  field  of  the sched_param
       structure.

       Changing the scheduling policy or priority, or both, of  a
       thread  can cause it to start executing or to be preempted
       by another thread. A thread  changes  its  own  scheduling
       policy  and  priority  by using the handle returned by the
       pthread_self(3) routine.

       This routine differs  from  pthread_attr_setschedpolicy(3)
       and  pthread_attr_setschedparam(3), in that those routines
       set the scheduling policy and  parameter  attributes  that
       are used to establish the scheduling priority and scheduling
 policy of a new thread when it  is  created.  However,
       this  routine changes the scheduling policy and parameters
       of an existing thread.

RETURN VALUES    [Toc]    [Back]

       If an error condition  occurs,  no  scheduling  policy  or
       parameters  are  changed  for  the target thread, and this
       routine returns an integer value indicating  the  type  of
       error.  Possible  return values are as follows: Successful
       completion.  The value specified by  policy  or  param  is
       invalid.  An attempt was made to set the scheduling policy
       or a parameter to an unsupported value.  The  caller  does
       not  have the appropriate privileges to set the scheduling
       policy or parameters of the specified thread.   The  value
       specified  by thread does not refer to an existing thread.

ERRORS    [Toc]    [Back]

       None

SEE ALSO    [Toc]    [Back]

       Functions:                  pthread_attr_setschedparam(3),
       pthread_attr_setschedpolicy(3),         pthread_create(3),
       pthread_self(3), sched_yield(3)

       Manuals: Guide to DECthreads and Programmer's Guide



                                         pthread_setschedparam(3)