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| 503 | |
503 | |
| 504 | =head2 IDLE WATCHERS |
504 | =head2 IDLE WATCHERS |
| 505 | |
505 | |
| 506 | $w = AnyEvent->idle (cb => <callback>); |
506 | $w = AnyEvent->idle (cb => <callback>); |
| 507 | |
507 | |
| 508 | Sometimes there is a need to do something, but it is not so important |
508 | Repeatedly invoke the callback after the process becomes idle, until |
| 509 | to do it instantly, but only when there is nothing better to do. This |
509 | either the watcher is destroyed or new events have been detected. |
| 510 | "nothing better to do" is usually defined to be "no other events need |
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| 511 | attention by the event loop". |
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| 512 | |
510 | |
| 513 | Idle watchers ideally get invoked when the event loop has nothing |
511 | Idle watchers are useful when there is a need to do something, but it |
| 514 | better to do, just before it would block the process to wait for new |
512 | is not so important (or wise) to do it instantly. The callback will be |
| 515 | events. Instead of blocking, the idle watcher is invoked. |
513 | invoked only when there is "nothing better to do", which is usually |
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514 | defined as "all outstanding events have been handled and no new events |
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515 | have been detected". That means that idle watchers ideally get invoked |
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516 | when the event loop has just polled for new events but none have been |
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517 | detected. Instead of blocking to wait for more events, the idle watchers |
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518 | will be invoked. |
| 516 | |
519 | |
| 517 | Most event loops unfortunately do not really support idle watchers (only |
520 | Unfortunately, most event loops do not really support idle watchers (only |
| 518 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
521 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
| 519 | will simply call the callback "from time to time". |
522 | will simply call the callback "from time to time". |
| 520 | |
523 | |
| 521 | Example: read lines from STDIN, but only process them when the |
524 | Example: read lines from STDIN, but only process them when the |
| 522 | program is otherwise idle: |
525 | program is otherwise idle: |
