The event manager state.

The event manager state.

Retrieve the system event manager for the capability on which the calling thread is running.

This function always returns Just the current thread's event manager when using the threaded RTS and Nothing otherwise.

Create a new event manager.

An I/O event.

Data is available to be read.

The file descriptor is ready to accept a write.

Callback invoked on I/O events.

A file descriptor registration cookie.

The lifetime of an event registration.

@since base-4.8.1.0

registerFd mgr cb fd evs lt registers interest in the events evs on the file descriptor fd for lifetime lt. cb is called for each event that occurs. Returns a cookie that can be handed to unregisterFd.

Drop a previous file descriptor registration.

Drop a previous file descriptor registration, without waking the event manager thread. The return value indicates whether the event manager ought to be woken.

Close a file descriptor in a race-safe way. It might block, although for a very short time; and thus it is interruptible by asynchronous exceptions.

Warning: since the TimeoutCallback is called from the I/O manager, it must not throw an exception or block for a long period of time. In particular, be wary of throwTo and killThread: if the target thread is making a foreign call, these functions will block until the call completes.

A timeout registration cookie.

Register a timeout in the given number of microseconds. The returned TimeoutKey can be used to later unregister or update the timeout. The timeout is automatically unregistered after the given time has passed.

Be careful not to exceed maxBound :: Int, which on 32-bit machines is only 2147483647 μs, less than 36 minutes.

Update an active timeout to fire in the given number of microseconds.

Be careful not to exceed maxBound :: Int, which on 32-bit machines is only 2147483647 μs, less than 36 minutes.

Unregister an active timeout.