Provided by: liblinux-epoll-perl_0.018-2_amd64 
NAME
Linux::Epoll - O(1) multiplexing for Linux
VERSION
version 0.018
SYNOPSIS
use Linux::Epoll;
my $epoll = Linux::Epoll->new();
$epoll->add($fh, 'in', sub {
my $events = shift;
do_something($fh) if $events->{in};
});
$epoll->wait while 1;
DESCRIPTION
Epoll is a multiplexing mechanism that scales up O(1) with number of watched files.
Linux::Epoll is a callback style epoll module, unlike other epoll modules available on
CPAN.
Types of events
• in
The associated filehandle is available for reading.
• out
The associated filehandle is available for writing.
• err
An error condition has happened on the associated filehandle. "wait" will always wait
on this event, it is not necessary to set this with "add" or "modify".
• prio
There is urgent data available for reading.
• et
Set edge triggered behavior for the associated filehandle. The default behavior is
level triggered. See you epoll(7) documentation for more information on what this
means.
Take note that when using edge triggered events, exceptions out of the wait can easily
cause events to be lost (when consuming to more than one event at a time).
• hup
A hang-up has happened on the associated filehandle. "wait" will always wait on this
event, it is not necessary to set this with "add" or "modify".
• rdhup
Stream socket peer closed the connection, or shut down the writing half of connection.
This flag is especially useful for writing simple code to detect peer shutdown when
using Edge Triggered monitoring.
• oneshot
Sets the one-shot behavior for the associated file descriptor. This means that after
an event is pulled out with "wait" the associated file descriptor is internally
disabled and no other events will be reported by the epoll interface. The user must
call "modify" to rearm the file descriptor with a new event mask.
• wakeup
If "oneshot" and "et" are clear and the process has the "CAP_BLOCK_SUSPEND"
capability, ensure that the system does not enter "suspend" or "hibernate" while this
event is pending or being processed. The event is considered as being "processed" from
the time when it is returned by a call to epoll_wait(2) until the next call to
epoll_wait(2) on the same epoll(7) file descriptor, the closure of that file
descriptor, the removal of the event file descriptor with EPOLL_CTL_DEL, or the
clearing of EPOLLWAKEUP for the event file descriptor with EPOLL_CTL_MOD.
• exclusive
Sets an exclusive wakeup mode for the epoll file descriptor that is being attached to
the target file descriptor, fd. When a wakeup event occurs and multiple epoll file
descriptors are attached to the same target file using "exclusive", one or more of the
epoll file descriptors will receive an event with "wait()". The default in this
scenario (when "exclusive" is not set) is for all epoll file descriptors to receive an
event. "exclusive" is thus useful for avoiding thundering herd problems in certain
scenarios.
If the same file descriptor is in multiple epoll instances, some with the "exclusive"
flag, and others without, then events will be provided to all epoll instances that did
not specify "exclusive", and at least one of the epoll instances that did specify
"exclusive".
The following values may be specified in conjunction with "exclusive": "in", "out",
"wakeup", and "et". "hup" and "err" can also be specified, but this is not required:
as usual, these events are always reported if they occur, regardless of whether they
are specified in events. Attempts to specify other values in events yield an error.
"exclusive" may be used only in an "add()" operation; attempts to employ it with
"modify" yield an error. If "exclusive" has been set using "add()", then a subsequent
"modify()" on the same epfd, fd pair yields an error. A call to "add(" that specifies
"exclusive" in events and specifies the target file descriptor fd as an epoll instance
will likewise fail. The error in all of these cases is "EINVAL".
METHODS
new()
Create a new epoll instance.
add($fh, $events, $callback)
Register the filehandle with the epoll instance and associate events $events and callback
$callback with it. $events may be either a string (e.g. 'in') or an arrayref (e.g. "[qw/in
out hup/]"). If a filehandle already exists in the set and "add" is called in non-void
context, it returns undef and sets $! to "EEXIST"; if the file can't be waited upon it
sets $! to "EPERM" instead. On all other error conditions an exception is thrown. The
callback gets a single argument, a hashref whose keys are the triggered events.
modify($fh, $events, $callback)
Change the events and callback associated on this epoll instance with filehandle $fh. The
arguments work the same as with "add". If a filehandle doesn't exist in the set and
"modify" is called in non-void context, it returns undef and sets $! to "ENOENT". On all
other error conditions an exception is thrown.
delete($fh)
Remove a filehandle from the epoll instance. If a filehandle doesn't exist in the set and
"delete" is called in non-void context, it returns undef and sets $! to "ENOENT". On all
other error conditions an exception is thrown.
wait($number = 1, $timeout = undef, $sigmask = undef)
Wait for up to $number events, where $number must be greater than zero. $timeout is the
maximal time "wait" will wait for events in fractional seconds. If it is undefined it may
wait indefinitely. $sigmask is the signal mask during the call. If it is not defined the
signal mask will be untouched. If interrupted by a signal it returns undef/an empty list
and sets $! to "EINTR". On all other error conditions an exception is thrown.
REQUIREMENTS
This module requires at least Perl 5.10 and Linux 2.6.19 to function correctly.
SEE ALSO
• IO::Epoll
• Sys::Syscall
• IO::Poll
AUTHOR
Leon Timmermans <leont@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2010 by Leon Timmermans.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.