8.16.0.4
5 Synchronizable Events
| (require scramble/evt) | package: scramble-lib |
procedure
(make-box-evt) → box-evt?
Returns a new box event. A box event becomes ready for synchronization
when it is filled with a value by box-evt-set!, and its synchronization
result is the value in the box. Once a box event becomes ready, it remains
ready, and its contents cannot be changed.
Box events are thread-safe and break-safe but not kill-safe: If a thread is
killed during a call to box-evt-set!, it is possible for the box event
to become damaged—
Examples:
> (define bxe (make-box-evt)) > (sync/timeout 0 bxe) #f
> (box-evt-set! bxe (list 1 2 3)) #t
> (sync/timeout 0 bxe) '(1 2 3)
> (box-evt-set! bxe (list 7 8 9)) #f
> (sync/timeout 0 bxe) '(1 2 3)
procedure
(box-evt-set! bxe v) → boolean?
bxe : box-evt? v : any/c
If bxe is not ready, then fills it with v, causing
bxe to become ready, and returns #t. If bxe is
already ready, returns #f without changing bxe’s contents.
procedure
(box-evt-ready? bxe) → boolean?
bxe : box-evt?
Returns #t if bxe is ready for synchronization, #f
otherwise.
Equivalent to (sync/timeout 0 (wrap-evt bxe (lambda (v) #t))).