EvCheck
final class EvCheck extends EvWatcher (View source)
Class EvCheck
EvPrepare and EvCheck watchers are usually used in pairs. EvPrepare watchers get invoked before the process blocks, EvCheck afterwards.
It is not allowed to call EvLoop::run() or similar methods or functions that enter the current event loop from either EvPrepare or EvCheck watchers. Other loops than the current one are fine, however. The rationale behind this is that one don't need to check for recursion in those watchers, i.e. the sequence will always be: EvPrepare -> blocking -> EvCheck , so having a watcher of each kind they will always be called in pairs bracketing the blocking call.
The main purpose is to integrate other event mechanisms into libev and their use is somewhat advanced. They could be used, for example, to track variable changes, implement custom watchers, integrate net-snmp or a coroutine library and lots more. They are also occasionally useful to cache some data and want to flush it before blocking.
It is recommended to give EvCheck watchers highest( Ev::MAXPRI ) priority, to ensure that they are being run before any other watchers after the poll (this doesn’t matter for EvPrepare watchers).
Also, EvCheck watchers should not activate/feed events. While libev fully supports this, they might get executed before other EvCheck watchers did their job.
Properties
| bool | $is_active | from EvWatcher | |
| bool | $is_pending | from EvWatcher | |
| mixed | $data | from EvWatcher | |
| int | $priority | from EvWatcher |
Methods
No description
Invokes the watcher callback with the given received events bit mask.
No description
Details
__construct(callable $callback, mixed $data = null, int $priority = 0)
No description
int
clear()
Clear watcher pending status.
If the watcher is pending, this method clears its pending status and returns its revents bitset (as if its callback was invoked). If the watcher isn't pending it does nothing and returns 0.
Sometimes it can be useful to "poll" a watcher instead of waiting for its callback to be invoked, which can be accomplished with this function.
feed(int $revents)
Feeds the given revents set into the event loop.
Feeds the given revents set into the event loop, as if the specified event had happened for the watcher.
EvLoop
getLoop()
Returns the loop responsible for the watcher.
invoke(int $revents)
Invokes the watcher callback with the given received events bit mask.
keepalive(bool $value = true)
Configures whether to keep the loop from returning.
Configures whether to keep the loop from returning. With keepalive value set to FALSE the watcher won't keep Ev::run() / EvLoop::run() from returning even though the watcher is active.
Watchers have keepalive value TRUE by default.
Clearing keepalive status is useful when returning from Ev::run() / EvLoop::run() just because of the watcher is undesirable. It could be a long running UDP socket watcher or so.
setCallback(callable $callback)
Sets new callback for the watcher.
start()
Starts the watcher.
Marks the watcher as active. Note that only active watchers will receive events.
stop()
Stops the watcher.
Marks the watcher as inactive. Note that only active watchers will receive events.
final static EvCheck
createStopped(mixed $callback, mixed $data = null, int $priority = 0)
No description