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get_priority(-Priority)

Get the priority of the currently executing goal.
-Priority
A variable.

Description

All goals in ECLiPSe execute under a certain priority. An execution can only be interrupted by the waking of a goal with a higher priority. Priorities are most relevant in data-driven algorithms, to specify that certain goals must do their work before others can meaningfully execute.

Priorities range from 1 (most urgent) to 12 (least urgent). The toplevel goal of an execution always runs at the lowest priority (12).

Warning: Although it is possible to write programs that only work correctly under a particular priority ordering, such practice is strongly discouraged. Priorities should only affect efficiency, never correctness.

Fail Conditions

None.

Resatisfiable

No.

Exceptions

(24) number expected
Priority is neither variable nor number.

Examples

    [eclipse 1]: get_priority(P).
    P = 12
    yes.

    [eclipse 2]: [user].
     p :- get_priority(P), writeln(prio=P).

    user       compiled traceable 120 bytes in 0.00 seconds
    yes.
    [eclipse 3]: suspend(p, 5, X->inst), X=1.
    prio = 5
    X = 1
    yes.

See Also

call_priority / 2, make_suspension / 3, make_suspension / 4, suspend / 3, suspend / 4, set_suspension_data / 3