trusty (7) sched.h.7posix.gz

NAME

       sched.h - execution scheduling (REALTIME)

SYNOPSIS

       #include <sched.h>

DESCRIPTION

       The  <sched.h>  header  shall  define the sched_param structure, which contains the scheduling parameters
       required for implementation of each supported scheduling policy. This structure shall  contain  at  least
       the following member:

              int       sched_priority        Process execution scheduling priority.

       In  addition,  if  _POSIX_SPORADIC_SERVER  or  _POSIX_THREAD_SPORADIC_SERVER  is defined, the sched_param
       structure defined in <sched.h> shall contain the following members in addition to those specified above:

              int             sched_ss_low_priority Low scheduling priority for
                                                    sporadic server.
              struct timespec sched_ss_repl_period  Replenishment period for
                                                    sporadic server.
              struct timespec sched_ss_init_budget  Initial budget for sporadic server.
              int             sched_ss_max_repl     Maximum pending replenishments for
                                                    sporadic server.

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

       Four scheduling policies are defined; others may be defined by  the  implementation.  The  four  standard
       policies are indicated by the values of the following symbolic constants:

       SCHED_FIFO
              First in-first out (FIFO) scheduling policy.

       SCHED_RR
              Round robin scheduling policy.

       SCHED_SPORADIC
              Sporadic server scheduling policy.

       SCHED_OTHER
              Another scheduling policy.

       The values of these constants are distinct.

       The following shall be declared as functions and may also be defined as macros. Function prototypes shall
       be provided.

              int    sched_get_priority_max(int);
              int    sched_get_priority_min(int);

              int    sched_getparam(pid_t, struct sched_param *);
              int    sched_getscheduler(pid_t);

              int    sched_rr_get_interval(pid_t, struct timespec *);

              int    sched_setparam(pid_t, const struct sched_param *);
              int    sched_setscheduler(pid_t, int, const struct sched_param *);

              int    sched_yield(void);

       Inclusion of the <sched.h> header may make visible all symbols from the <time.h> header.

       The following sections are informative.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <time.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
       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.opengroup.org/unix/online.html .