48 lines
1.3 KiB
Text
48 lines
1.3 KiB
Text
.TH rtapi_prio "3rtapi" "2006-10-12" "LinuxCNC Documentation" "RTAPI"
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.SH NAME
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rtapi_prio \- thread priority functions
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.SH SYNTAX
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.HP
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int rtapi_prio_highest()
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.HP
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int rtapi_prio_lowest()
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.HP
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int rtapi_prio_next_higher(int \fIprio\fR)
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.HP
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int rtapi_prio_next_lower(int \fIprio\fR)
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.SH ARGUMENTS
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.IP \fIprio\fR
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A value returned by a prior \fBrtapi_prio_xxx\fR call
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.SH DESCRIPTION
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The \fBrtapi_prio_xxxx\fR functions provide a portable way to set task
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priority. The mapping of actual priority to priority number depends on the
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RTOS. Priorities range from \fBrtapi_prio_lowest\fR to
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\fBrtapi_prio_highest\fR, inclusive. To use this API, use one of two methods:
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.IP 1)
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Set your lowest priority task to \fBrtapi_prio_lowest\fR, and for
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each task of the next lowest priority, set their priorities to
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\fBrtapi_prio_next_higher(previous)\fR.
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.IP 2)
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Set your highest priority task to \fBrtapi_prio_highest\fR, and
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for each task of the next highest priority, set their priorities
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to \fBrtapi_prio_next_lower(previous)\fR.
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.PP
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N.B. A high priority task will preempt or interrupt a lower priority
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task. Linux is always the lowest priority!
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.SH REALTIME CONSIDERATIONS
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Call these functions only from within init/cleanup code, not from realtime
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tasks.
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.SH RETURN VALUE
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Returns an opaque real-time priority number.
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.SH SEE ALSO
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\fBrtapi_task_new(3rtapi)\fR
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