Scroll to navigation

rtapi_prio(3rtapi) RTAPI rtapi_prio(3rtapi)

NAME

rtapi_prio - thread priority functions

SYNTAX

int rtapi_prio_highest()

int rtapi_prio_lowest()

int rtapi_prio_next_higher(int prio)

int rtapi_prio_next_lower(int prio)

ARGUMENTS

A value returned by a prior rtapi_prio_xxx call

DESCRIPTION

The rtapi_prio_xxxx functions provide a portable way to set task priority. The mapping of actual priority to priority number depends on the RTOS. Priorities range from rtapi_prio_lowest to rtapi_prio_highest, inclusive. To use this API, use one of two methods:

1)
Set your lowest priority task to rtapi_prio_lowest, and for each task of the next lowest priority, set their priorities to rtapi_prio_next_higher(previous).

2)
Set your highest priority task to rtapi_prio_highest, and for each task of the next highest priority, set their priorities to rtapi_prio_next_lower(previous).

N.B. A high priority task will preempt or interrupt a lower priority task. Linux is always the lowest priority!

REALTIME CONSIDERATIONS

Call these functions only from within init/cleanup code, not from realtime tasks.

RETURN VALUE

Returns an opaque real-time priority number.

SEE ALSO

rtapi_task_new(3rtapi)

2006-10-12 LinuxCNC Documentation