sched_setparam(2) — DG/UX R4.11



sched_setparam(2)                 SDK R4.11                sched_setparam(2)


NAME
       sched_setparam - set the scheduling priority for a process

SYNOPSIS
       #include <sched.h>

       int schedsetparam (pid, *priority)
            pidt            pid;
            struct schedparam*priority;

DESCRIPTION
       Use schedsetparam(2) to set the scheduling priority of process pid
       to the value indicated in priority. The POSIX-designated structure
       that priority points to is:

       struct schedparam
           {
           int schedpriority;
           };

       If pid is 0, this call sets the priority of the calling process.

       The larger the number in schedpriority, the higher the priority.  To
       find out the priority range for a given pid, use
       schedgetscheduler(2) to get its scheduling policy, then use
       schedgetprioritymax(2) and schedgetprioritymin(2) to get the
       range defined by that policy.

       Only a calling process with the appropriate privilege can set a
       priority higher than the current priority. A priority that is lower
       than or equal to the current priority may be set either by a calling
       process having appropriate privilege or by a process having an
       effective user id matching that of pid.  For systems supporting the
       DG/UX Capability Option, appropriate privilege is defined as having
       one or more specific capabilities enabled in the effective capability
       set of the calling process.  See capdefaults(5) for the default
       capability for this system call.

       On systems without the DG/UX Capability Option, appropriate privilege
       means that the process has an effective UID of root.  See the
       appropriateprivilege(5) man page for more information.

       If this call fails, the priority of pid is not changed.

   Note
        * This routine is based on POSIX realtime extension document P1003.4
          draft 14. It is therefore subject to change.

        * Compilation of a source file using this routine requires that
          feature macro _POSIX4_DRAFT_SOURCE be defined.  This feature macro
          is not enabled by any other feature macro, nor does it enable any
          other feature macro.

        * The compiled routine must be linked to library librte.a.

RETURN VALUE
       If successful, schedsetparam returns 0. If unsuccessful, the routine
       returns -1 and sets ERRNO to one of the following:

        EFAULT The address of priority is bad.

        EINVAL The priority value in schedpriority is outside the range
               defined for the scheduling policy of pid.

        EPERM  The caller does not have permission to set the scheduling
               priority of pid.

        ESRCH  Process pid doesn't exist or is negative.

SEE ALSO
       schedgetparam(2), schedsetscheduler(2), schedgetscheduler(2),
       schedyield(2), schedgetprioritymax(2), schedgetprioritymin(2),
       schedrrgetinterval(2), appropriateprivilege(5).
       capdefaults(5).


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