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epoll - I/O event notification facility


use epoll;

my $epoll = epoll.new(maxevents => 1); # 1 is default

$epoll.add($file-descriptor, :in, :out, :priority, :edge-triggered);

# timeout in milliseconds, default -1 = block forever
for $epoll.wait(:2000timeout)
    say "{.fd} is ready for reading" if .in;
    say "{.fd} is ready for writing" if .out;

# Or use chained calls:

for epoll.new.add(0, :in).wait
    say "ready to read on {.fd}" if .in;


Simple low level interface around the Linux epoll(7) I/O event notification facility. It can monitor multiple file descriptors to see if I/O is possible on any of them. Mainly useful for interfacing with other NativeCall modules, since Perl itself has a rich I/O system. If you really want to use this with Perl IO::Handles, you can use native-descriptor() to get a suitable descriptor.

class epoll

Create a new epoll object. Maxevents is the maximum number of events that can be returned from a single call to wait.

:inEPOLLINready for read
:outEPOLLOUTready for write
:priorityEPOLLPRIurgent data available for read
:edge-triggeredEPOLLETEdge Triggered
:one-shotEPOLLONESHOTDisables after 1 event
:modEPOLL_CTL_MODModify an existing file descriptor

:mod is equivalent to EPOLL_CTL_MOD to change the events for a file descriptor already added. It will also re-enable a file descriptor disabled by :one-shot mode.

For convenience, always returns the object itself, so you can chain calls.

Remove a file descriptor previously added.

Wait for 1 or more events to occur on the add()ed file descriptors. You can specify an optional timeout in milliseconds.

Returns a List of up up to $maxevents epoll-events.

class epoll-event

The file descriptor for the event.

A bitmask of the events that occurred. You can check them like this:

if $event.events +& EPOLLIN {...}

or use the much easier:

Ready to read

Ready to write


Throws Ad-hoc exceptions for any errors.

(Should save errno, and make real Exceptions -- patches welcome!)


epoll is a Linux specific mechanism, and is typically not available on other architectures.


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