Headers                                            sched.h(3HEAD)



NAME
     sched.h, sched - execution scheduling

SYNOPSIS
     #include <sched.h>


DESCRIPTION
     The <sched.h>  header  defines  the  sched_param  structure,
     which contains the scheduling parameters required for imple-
     mentation of each supported scheduling policy.  This  struc-
     ture contains the following member:

       int    sched_priority    process execution scheduling priority



     Each process is controlled by an associated scheduling  pol-
     icy  and priority. Associated with each policy is a priority
     range.  Each policy definition specifies the minimum  prior-
     ity range for that policy. The priority ranges for each pol-
     icy may overlap the priority ranges of other policies.


     The scheduling policies are indicated by the values  of  the
     following symbolic constants:

     SCHED_OTHER     Processes are scheduled according to the
                     traditional Time-Sharing Class (TS) policy
                     as described in priocntl(2).


     SCHED_FIFO      Processes are scheduled in the Real-Time (RT)
                     scheduling class, according  to  the
                     First-In-First-Out  (FIFO) policy. Processes
                     scheduled to this policy, if not  pre-empted
                     by  a  higher  priority  or interrupted by a
                     signal, will proceed until completion.


     SCHED_RR        Processes are scheduled in the Real-Time (RT)
                     scheduling class, according  to  the
                     Round-Robin (RR) policy. Processes scheduled
                     to this  policy,  if  not  pre-empted  by  a
                     higher  priority or interrupted by a signal,
                     will execute for a time period, returned  by
                     sched_rr_get_interval(3RT) or by the system.


     SCHED_IA        Processes are  scheduled  according  to  the
                     Inter-Active  Class (IA) policy as described
                     in priocntl(2).


     SCHED_FSS       Processes are  scheduled  according  to  the
                     Fair-Share  Class (FSS) policy as described
                     in priocntl(2).


     SCHED_FX        Processes are  scheduled  according  to  the
                     Fixed-Priority  Class (FX) policy as described
                     in priocntl(2).


     The values of these constants are distinct.


     Inclusion of the <sched.h> header will make visible  symbols
     defined in the header <time.h>.

SEE ALSO
     priocntl(2),
     sched_get_priority_max(3RT), sched_get_priority_min(3RT),
     sched_rr_get_interval(3RT), time.h(3HEAD)