NAME

POE - the Perl Operating Environment

SYNOPSIS

use POE;

DESCRIPTION

In general, POE provides "kernel" services, including select(2), events signals, alarms and reusable boilerplates for common functions.

In specific, POE uses POE::Kernel and POE::Session for you.

CLASSES

• POE::Kernel - main loop; select(2), signal, alarm, event services

• POE::Session - state machine managed by POE::Kernel

• POE::Driver (abstract) - drive (read and write) an IO::Handle

• POE::Driver::SysRW - sysread and syswrite on an IO::Handle

• POE::Filter (abstract) - bidirectional stream cooker; converts raw data to something useful (such as lines), and back

• POE::Filter::Line - break input into lines; add newlines to output

• POE::Wheel (abstract) - a way to extend POE::Session by adding or removing event handlers from state machines

• POE::Wheel::ReadWrite - manage read/write states for a session

• POE::Wheel::ListenAccept - accept incoming TCP socket connections

• POE::Wheel::FollowTail - watch the end of an ever-growing file

EXAMPLES

• tests/followtail.perl

  Starts 21 sessions, and runs them until SIGINT. 10 sessions write to dummy log files; 10 sessions follow the log tails; one session spins its wheels to make sure things are not blocking.

• tests/forkbomb.perl

  Starts one session whose job is to continually start copies of itself (and occasionally quit). A counter limits this test to about 150 total sessions, and the kernel will respond to SIGINT by killing everything and exiting.

  This is an excellent shakedown of parent/child relationships and signals.

• tests/selects.perl

  Starts two sessions, and runs until SIGINT. The first session is a TCP chargen server; the second is a simple TCP client that connects to the first. The client session has a limiter that causes the session to exit after printing a few chargen lines.

  POE::Wheel::ReadWrite and POE::Wheel::ListenAccept were based on the code here.

  This was the second test, written to exercise the select(2) logic in POE::Kernel.

• tests/sessions.perl

  Starts five sessions that loop a few times and stop. It was written to exercise the POE::Kernel event queue.

• tests/signals.perl

  One session that prints out a dot every second and recognizes SIGINT.

BUGS

POE::Kernel will exit on some signals, even if they are caught by sessions. This behavior can be evil for things that don't especially want to go away, so don't depend on it, okay? Thanks!

Signals just go to sessions in willy-nilly order. This may not be desirable, but it was quick to implement.

CONTACT AND COPYRIGHT

Copyright 1998 Rocco Caputo <troc@netrus.net>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.