{ "mode": "perldoc", "parameter": "POE", "section": "", "url": "https://www.chedong.com/phpMan.php/perldoc/POE/json", "generated": "2026-06-11T19:52:35Z", "synopsis": "#!/usr/bin/perl\nuse warnings;\nuse strict;\nuse POE; # Auto-includes POE::Kernel and POE::Session.\nsub handlerstart {\nmy ($kernel, $heap, $session) = @[KERNEL, HEAP, SESSION];\nprint \"Session \", $session->ID, \" has started.\\n\";\n$heap->{count} = 0;\n$kernel->yield('increment');\n}\nsub handlerincrement {\nmy ($kernel, $heap, $session) = @[KERNEL, HEAP, SESSION];\nprint \"Session \", $session->ID, \" counted to \", ++$heap->{count}, \".\\n\";\n$kernel->yield('increment') if $heap->{count} < 10;\n}\nsub handlerstop {\nprint \"Session \", $[SESSION]->ID, \" has stopped.\\n\";\n}\nfor (1..10) {\nPOE::Session->create(\ninlinestates => {\nstart => \\&handlerstart,\nincrement => \\&handlerincrement,\nstop => \\&handlerstop,\n}\n);\n}\nPOE::Kernel->run();\nexit;", "sections": { "NAME": { "content": "POE - portable multitasking and networking framework for any event loop\n", "subsections": [] }, "SYNOPSIS": { "content": "#!/usr/bin/perl\n\nuse warnings;\nuse strict;\n\nuse POE; # Auto-includes POE::Kernel and POE::Session.\n\nsub handlerstart {\nmy ($kernel, $heap, $session) = @[KERNEL, HEAP, SESSION];\nprint \"Session \", $session->ID, \" has started.\\n\";\n$heap->{count} = 0;\n$kernel->yield('increment');\n}\n\nsub handlerincrement {\nmy ($kernel, $heap, $session) = @[KERNEL, HEAP, SESSION];\nprint \"Session \", $session->ID, \" counted to \", ++$heap->{count}, \".\\n\";\n$kernel->yield('increment') if $heap->{count} < 10;\n}\n\nsub handlerstop {\nprint \"Session \", $[SESSION]->ID, \" has stopped.\\n\";\n}\n\nfor (1..10) {\nPOE::Session->create(\ninlinestates => {\nstart => \\&handlerstart,\nincrement => \\&handlerincrement,\nstop => \\&handlerstop,\n}\n);\n}\n\nPOE::Kernel->run();\nexit;\n", "subsections": [] }, "DESCRIPTION": { "content": "POE is a framework for cooperative, event driven multitasking and networking in Perl. Other\nlanguages have similar frameworks. Python has Twisted. TCL has \"the event loop\".\n\nPOE provides a unified interface for several other event loops, including select(), IO::Poll,\nGlib, Gtk, Tk, Wx, and Gtk2. Many of these event loop interfaces were written by others, with\nthe help of POE::Test::Loops. They may be found on the CPAN.\n\nPOE achieves its high degree of portability to different operating systems and Perl versions by\nbeing written entirely in Perl. CPAN hosts optional XS modules for POE if speed is more\ndesirable than portability.\n\nPOE is designed in layers. Each layer builds atop the lower level ones. Programs are free to use\nPOE at any level of abstraction, and different levels can be mixed and matched seamlessly within\na single program. Remember, though, that higher-level abstractions often require more resources\nthan lower-level ones. The conveniences they provide are not free.\n\nPOE's bundled abstraction layers are the tip of a growing iceberg. Sprocket, POE::Stage, and\nother CPAN distributions build upon this work. You're encouraged to look around.\n\nNo matter how high you go, though, it all boils down to calls to POE::Kernel. So your\ndown-to-earth code can easily cooperate with stratospheric systems.\n", "subsections": [ { "name": "Layer 1: Kernel and Sessions", "content": "The lowest public layer is comprised of POE::Kernel, POE::Session, and other session types.\n\nPOE::Kernel does most of the heavy lifting. It provides a portable interface for filehandle\nactivity detection, multiple alarms and other timers, signal handling, and other less-common\nfeatures.\n\nPOE::Session and derived classes encapsulate the notion of an event driven task. They also\ncustomize event dispatch to a particular calling convention. POE::NFA, for example, is more of a\nproper state machine. The CPAN has several other kinds of sessions.\n\nEverything ultimately builds on these classes or the concepts they implement. If you're short on\ntime, the things to read besides this are POE::Kernel and POE::Session.\n" }, { "name": "Layer 2: Wheels, Filters, and Drivers", "content": "POE::Wheel objects are dynamic mix-ins for POE::Session instances. These \"wheels\" perform very\ncommon, generic tasks in a highly reusable and customizable way. POE::Wheel::ReadWrite, for\nexample, implements non-blocking buffered I/O. Nearly everybody needs this, so why require\npeople to reinvent it all the time?\n\nPOE::Filter objects customize wheels in a modular way. Filters act as I/O layers, turning raw\nstreams into structured data, and serializing structures into something suitable for streams.\nThe CPAN also has several of these.\n\nDrivers are where the wheels meet the road. In this case, the road is some type of file handle.\nDrivers do the actual reading and writing in a standard way so wheels don't need to know the\ndifference between send() and syswrite().\n\nPOE::Driver objects get relatively short shrift because very few are needed. The most common\ndriver, POE::Driver::SysRW is ubiquitous and also the default, so most people will never need to\nspecify one.\n" }, { "name": "Layer 3: Components", "content": "POE::Component classes are essentially Perl classes that use POE to perform tasks in a\nnon-blocking or cooperative way. This is a very broad definition, and POE components are all\nover the abstraction map.\n\nMany components, such as POE::Component::Server::SMTP, encapsulate the generic details of an\nentire application. Others perform rather narrow tasks, such as\nPOE::Component::DirWatch::Object.\n\nPOE components are often just plain Perl objects. The previously mentioned\nPOE::Component::DirWatch::Object uses Moose. Other object and meta-object frameworks are\ncompatible.\n\nAlso of interest is POE::Component::Generic, which allows you to create a POE component from\nnearly any blocking module.\n\nThere are quite a lot of components on the CPAN.\n\n" }, { "name": "Layer 4 and Beyond: Frameworks and Object Metaphors", "content": "It's possible to abstract POE entirely behind a different framework. In fact we encourage people\nto write domain-specific abstractions that entirely hide POE if necessary. The nice thing here\nis that even at these high levels of abstraction, things will continue to interoperate all the\nway down to layer 1.\n\nTwo examples of ultra-high level abstraction are Sprocket, a networking framework that does its\nown thing, and POE::Stage, which is POE's creator's attempt to formalize and standardize POE\ncomponents.\n\nIt is also possible to communicate between POE processes. This is called IKC, for *Inter-Kernel\nCommunication*. There are a few IKC components on the CPAN\n(), notably POE::Component::IKC and POE::TIKC.\n" }, { "name": "Layer 0: POE's Internals", "content": "POE's layered architecture continues below the surface. POE's guts are broken into specific\nPOE::Loop classes for each event loop it supports. Internals are divided up by type, giving\nPOE::Resource classes for Aliases, Controls, Events, Extrefs, FileHandles, SIDs, Sessions and\nSignals.\n\nPOE::Kernel's APIs are extensible through POE::API mix-in classes. Some brave souls have even\npublished new APIs on CPAN, such as POE::API::Peek (which gives you access to some of the\ninternal POE::Resource methods).\n\nBy design, it's possible to implement new POE::Kernel guts by creating another POE::Resource\nclass. One can then expose the functionality with a new POE::API mix-in.\n" } ] }, "DOCUMENTATION ROADMAP": { "content": "You're reading the main POE documentation. It's the general entry point to the world of POE. You\nalready know this, however, so let's talk about something more interesting.\n", "subsections": [ { "name": "Basic Features", "content": "POE's basic features are documented mainly in POE::Kernel and POE::Session. Methods are\ndocumented in the classes that implement them. Broader concepts are covered in the most\nappropriate class, and sometimes they are divided among classes that share in their\nimplementation.\n" }, { "name": "Basic Usage", "content": "Basic usage, even for POE.pm, is documented in POE::Kernel. That's where most of POE's work is\ndone, and POE.pm is little more than a class loader.\n\n@[KERNEL, HEAP, etc.]\nEvent handler calling conventions, that weird @[KERNEL, HEAP] stuff, is documented in\nPOE::Session. That's because POE::Session implements the calling convention, and other session\ntypes often do it differently.\n" }, { "name": "Base Classes Document Common Features", "content": "The POE::Wheel, POE::Driver, POE::Filter, and POE::Component base classes describe what's common\namong each class. It's a good idea to at least skim the base class documentation since the\nsubclasses tend not to rehash the common things.\n\nPOE::Queue, POE::Resource, and POE::Loop document the concepts and sometimes the standard\ninterfaces behind multiple subclasses. You're encouraged to have a look.\n" }, { "name": "Helper Classes", "content": "POE includes some helper classes for portability. POE::Pipe, and its subclasses\nPOE::Pipe::OneWay and POE::Pipe::TwoWay are portable pipes.\n" }, { "name": "Event Loop Bridges", "content": "POE::Loop documents and specifies the interface for all of POE's event loop bridges. The\nindividual classes may document specific details, but generally they adhere to the spec strongly\nenough that they don't need to.\n\nMany of the existing POE::Loop bridges provided in POE's base distribution will move out to\nseparate distributions shortly. The documentation will probably remain the same, however.\n\nPOE::Queue and POE::Queue::Array\nPOE's event queue is basically a priority heap implemented as an ordered array. POE::Queue\ndocuments the standard interface for POE event queues, and POE::Queue::Array implements the\nordered array queue. Tony Cook has released POE::XS::Queue::Array, which is a drop-in C\nreplacement for POE::Queue::Array. You might give it a try if you need more performance. POE's\nevent queue is some of the hottest code in the system.\n" }, { "name": "This Section Isn't Complete", "content": "Help organize the documentation. Obviously we can't think of everything. We're well aware of\nthis and welcome audience participation.\n" }, { "name": "See SEE ALSO", "content": "Wherever possible, the SEE ALSO section will cross-reference one module to related ones.\n" }, { "name": "Don't Forget the Web", "content": "Finally, there are many POE resources on the web. The CPAN contains a growing number of POE\nmodules. hosts POE's wiki, which includes tutorials, an extensive set of\nexamples, documentation, and more. Plus it's a wiki, so you can trivially pitch in your two\ncents.\n" } ] }, "SYSTEM REQUIREMENTS": { "content": "POE's basic requirements are rather light. Most are included with modern versions of Perl, and\nthe rest (if any) should be generally portable by now.\n\nTime::HiRes is highly recommended, even for older Perls that don't include it. POE will work\nwithout it, but alarms and other features will be much more accurate if it's included.\nPOE::Kernel will use Time::HiRes automatically if it's available.\n\nPOE::Filter::Reference needs a module to serialize data for transporting it across a network. It\nwill use Storable, FreezeThaw, YAML, or some other package with freeze() and thaw() methods. It\ncan also use Compress::Zlib to conserve bandwidth and reduce latency over slow links, but it's\nnot required.\n\nIf you want to write web servers, you'll need to install libwww-perl, which requires libnet.\nThis is a small world of modules that includes HTTP::Status, HTTP::Request, HTTP::Date, and\nHTTP::Response. They are generally good to have, and modern versions of Perl even include them.\n\nPrograms that use POE::Wheel::Curses will of course require the Curses module, which in turn\nrequires some sort of curses library.\n\nIf you're using POE with Tk, you'll need Tk installed.\n\nAnd other obvious things. Let us know if we've overlooked a non-obvious detail.\n", "subsections": [] }, "COMPATIBILITY ISSUES": { "content": "One of POE's design goals is to be as portable as possible. That's why it's written in \"Plain\nPerl\". XS versions of POE modules are available as third-party distributions. Parts of POE that\nrequire nonstandard libraries are optional, and not having those libraries should not prevent\nPOE from installing.\n\nDespite Chris Williams' efforts, we can't test POE everywhere. Please see the GETTING HELP\nsection if you run into a problem.\n\nPOE is expected to work on most forms of UNIX, including FreeBSD, MacOS X, Linux, Solaris. Maybe\neven AIX and QNX, but we're not sure.\n\nPOE is also tested on Windows XP, using the latest version of ActiveState, Strawberry and Cygwin\nPerl. POE is fully supported with Strawberry Perl, as it's included in the Strawberry\ndistribution.\n\nOS/2 and MacOS 9 have been reported to work in the past, but nobody seems to be testing there\nanymore. Reports and patches are still welcome.\n\nPast versions of POE have been tested with Perl versions as far back as 5.6.2 and as recent as\n\"blead\", today's development build. We can no longer guarantee each release will work\neverywhere, but we will be happy to work with you if you need special support for a really old\nsystem. You can always use older POE releases that works on your version, please check BackPAN\n.\n\nPOE's quality is due in large part to the fine work of Chris Williams and the other CPAN\ntesters. They have dedicated resources towards ensuring CPAN distributions pass their own tests,\nand we watch their reports religiously. You can, too. The latest POE test reports can be found\nat .\n\nThanks also go out to Benjamin Smith and the 2006 Google Summer of Code. Ben was awarded a grant\nto improve POE's test suite, which he did admirably.\n", "subsections": [ { "name": "Windows Issues", "content": "POE seems to work very nicely with Perl compiled for Cygwin. If you must use ActiveState Perl,\nplease use the absolute latest version. ActiveState Perl's compatibility fluctuates from one\nbuild to another, so we tend not to support older releases.\n\nWindows and ActiveState Perl are considered an esoteric platform due to the complex interactions\nbetween various versions. POE therefore relies on user feedback and support here.\n\nA number of people have helped bring POE's Windows support this far, through contributions of\ntime, patches, and other resources. Some of them are: Sean Puckett, Douglas Couch, Andrew Chen,\nUhlarik Ondoej, Nick Williams, and Chris Williams (no relation).\n\nLinux/Unix Issues\npty woes\nSome distributions chose to not completely setup the pseudo-tty support. This is needed for\nPOE::Wheel::Run to interact with the subprocess. If you see something like this while running\n\"make test\" please look at your distribution's documentation on how to fix it. For example, on\nDebian-based systems the solution was to execute \"sudo apt-get install udev\".\n\nt/30loops/iopoll/wheelrun.t ..................... 1/99\nptyallocate(nonfatal): posixopenpt(): No such file or directory at /usr/local/lib/perl/5.10.0/IO/Pty.pm line 24.\n...\nCannot open a pty at /home/apoc/poe/blib/lib/POE/Wheel/Run.pm line 251\nCompilation failed in require at t/30loops/iopoll/wheelrun.t line 24.\n# Looks like you planned 99 tests but ran 5.\n# Looks like your test exited with 22 just after 5.\nt/30loops/iopoll/wheelrun.t ..................... Dubious, test returned 22 (wstat 5632, 0x1600)\n" }, { "name": "Other Compatibility Issues", "content": "None currently known. See GETTING HELP below if you've run into something.\n" } ] }, "GETTING HELP": { "content": "POE's developers take pride in its quality. If you encounter a problem, please let us know.\n\nPOE's Request Tracker\nYou're welcome to e-mail questions and bug reports to . This is not a\nrealtime support channel, though. If you need a more immediate response, try one of the methods\nbelow.\n\nPOE's Mailing List\nPOE has a dedicated mailing list where developers and users discuss the software and its use.\nYou're welcome to join us. Send an e-mail to for subscription instructions.\nThe subject and message body are ignored.\n\nPOE's Web Site\n contains recent information, tutorials, and examples. It's also a wiki, so\npeople are invited to share tips and code snippets there as well.\n\nPOE's Source Code\nThe following command will fetch the most current version of POE into the \"poe\" subdirectory:\n\ngit clone https://github.com/rcaputo/poe.git\n", "subsections": [ { "name": "SourceForge", "content": "http://sourceforge.net/projects/poe/ is POE's project page.\n\nInternet Relay Chat (IRC)\nirc.perl.org channel #poe is an informal place to waste some time and maybe even discuss Perl\nand POE. Consider an SSH relay if your workplace frowns on IRC. But only if they won't fire you\nif you're caught.\n" }, { "name": "Personal Support", "content": "Unfortunately we don't have resources to provide free one-on-one personal support anymore. We'll\ndo it for a fee, though. Send Rocco an e-mail via his CPAN address.\n" } ] }, "SEE ALSO": { "content": "Broken down by abstraction layer.\n", "subsections": [ { "name": "Layer 1", "content": "POE::Kernel, POE::Session, POE::NFA\n" }, { "name": "Layer 2", "content": "POE::Wheel, POE::Wheel::Curses, POE::Wheel::FollowTail, POE::Wheel::ListenAccept,\nPOE::Wheel::ReadLine, POE::Wheel::ReadWrite, POE::Wheel::Run, POE::Wheel::SocketFactory\n\nPOE::Driver, POE::Driver::SysRW\n\nPOE::Filter, POE::Filter::Block, POE::Filter::Grep, POE::Filter::HTTPD, POE::Filter::Line,\nPOE::Filter::Map, POE::Filter::RecordBlock, POE::Filter::Reference, POE::Filter::Stackable,\nPOE::Filter::Stream\n" }, { "name": "Layer 3", "content": "POE::Component, POE::Component::Client::TCP, POE::Component::Server::TCP\n" }, { "name": "Layer 0", "content": "POE::Loop, POE::Loop::Event, POE::Loop::Gtk, POE::Loop::IOPoll, POE::Loop::Select,\nPOE::Loop::Tk\n\nPOE::Queue, POE::Queue::Array\n\nPOE::Resource, POE::Resource::Aliases, POE::Resource::Events, POE::Resource::Extrefs,\nPOE::Resource::FileHandles, POE::Resource::SIDs, POE::Resource::Sessions, POE::Resource::Signals\n" }, { "name": "Helpers", "content": "POE::Pipe, POE::Pipe::OneWay, POE::Pipe::TwoWay\n" }, { "name": "Home Page", "content": "http://poe.perl.org/\n" }, { "name": "Bug Tracker", "content": "https://rt.cpan.org/Dist/Display.html?Status=Active&Queue=POE\n" }, { "name": "Repositories and Changes", "content": "You can browse the POE source and complete change logs at https://github.com/rcaputo/poe. It\nalso provides an RSS news feed for those who want to follow development in near-realtime.\n" }, { "name": "Other Resources", "content": "https://metacpan.org/module/POE\n\nhttp://search.cpan.org/dist/POE\n\nAUTHORS & COPYRIGHT\nPOE is the combined effort of quite a lot of people. This is an incomplete list of some early\ncontributors. A more complete list can be found in POE's change log.\n\nAnn Barcomb\nAnn Barcomb is , aka \"kudra\". Ann contributed large portions of\nPOE::Simple and the code that became the ReadWrite support in POE::Component::Server::TCP. Her\nideas also inspired Client::TCP component, introduced in version 0.1702.\n\nArtur Bergman\nArtur Bergman is . He contributed many hours' work into POE and quite a lot of\nideas. Years later, I decide he's right and actually implement them.\n\nArtur is the author of Filter::HTTPD and Filter::Reference, as well as bits and pieces\nthroughout POE. His feedback, testing, design and inspiration have been instrumental in making\nPOE what it is today.\n\nArtur is investing his time heavily into perl 5's iThreads and PONIE at the moment. This\nproject has far-reaching implications for POE's future.\n\nJos Boumans\nJos Boumans is , aka \"kane\". Jos is a major driving force behind the\nPOE::Simple movement and has helped inspire the POE::Components for TCP clients and servers.\n\nMatt Cashner\nMatt Cashner is , aka \"sungo\". Matt is one of POE's core developers. He's\nspearheaded the movement to simplify POE for new users, flattening the learning curve and\nmaking the system more accessible to everyone. He uses the system in mission critical\napplications, folding feedback and features back into the distribution for everyone's\nenjoyment.\n\nAndrew Chen\nAndrew Chen is . Andrew is the resident POE/Windows guru. He\ncontributes much needed testing for Solaris on the SPARC and Windows on various Intel\nplatforms.\n\nDouglas Couch\nDouglas Couch is . Douglas helped port and maintain POE for Windows early\non.\n\nJeffrey Goff\nJeffrey Goff is . Jeffrey is the author of several POE modules,\nincluding a tokenizing filter and a component for managing user information, PoCo::UserBase.\nHe's also co-author of \"A Beginner's Introduction to POE\" at www.perl.com.\n\nPhilip Gwyn\nPhilip Gwyn is . He extended the Wheels I/O abstraction to support\nhot-swappable filters, and he eventually convinced Rocco that unique session and kernel IDs\nwere a good thing.\n\nPhilip also enhanced POE::Filter::Reference to support different serialization methods. He has\nalso improved POE's quality by finding and fixing several bugs. He provided POE a much needed\ncode review around version 0.06.\n\nLately, Philip tracked down the race condition in signal handling and fixed it with the signal\npipe.\n\nArnar M. Hrafnkelsson\nArnar is . Addi tested POE and POE::Component::IRC on Windows, finding bugs\nand testing fixes. He appears throughout the Changes file. He has also written \"cpoe\", which\nis a POE-like library for C.\n\nDave Paris\nDave Paris is . Dave tested and benchmarked POE around version 0.05,\ndiscovering some subtle (and not so subtle) timing problems. The pre-forking server sample was\nhis idea. Versions 0.06 and later scaled to higher loads because of his work. He has\ncontributed a lot of testing and feedback, much of which is tagged in the Changes file as\na-mused. The man is scarily good at testing and troubleshooting.\n\nDieter Pearcey\nDieter Pearcey is . He goes by several Japanese nicknames.\nDieter's current area of expertise is in Wheels and Filters. He greatly improved\nPOE::Wheel::FollowTail, and his Filter contributions include the basic Block filter, as well\nas Stackable, RecordBlock, Grep and Map.\n\nPlixer International\nPlixer International is at . Their sponsorship has helped POE 1.300 and\nbeyond be significantly more robust using iThreads, especially when using fork() in Windows.\n\nRobert Seifer\nRobert Seifer is . He rotates IRC nicknames regularly.\n\nRobert contributed entirely too much time, both his own and his computers, towards the\ndetection and eradication of a memory corruption bug that POE tickled in earlier Perl\nversions. In the end, his work produced a simple compile-time hack that worked around a\nproblem relating to anonymous subs, scope and @{} processing.\n\nMatt Sergeant\nMatt contributed \"POE::Kernel::Poll\", a more efficient way to watch multiple files than\nselect(). It's since been moved to POE::Loop::IOPoll.\n\nRichard Soderberg\nRichard Soderberg is , aka \"coral\". Richard is a collaborator on several\nside projects involving POE. His work provides valuable testing and feedback from a user's\npoint of view.\n\nDennis Taylor\nDennis Taylor is . Dennis has been testing, debugging and patching bits\nhere and there, such as Filter::Line which he improved by leaps in 0.1102. He's also the\nauthor of POE::Component::IRC, the widely popular POE-based successor to his wildly popular\nNet::IRC library.\n\nDavid Davis\nDavid Davis, aka Xantus is . David contributed patches to the HTTPD filter,\nand added CALLERSTATE to POE::Session. He is the author of Sprocket, a networking framework\nbuilt on POE.\n\nOthers?\nPlease contact the author if you've been forgotten and would like to be included here.\n" }, { "name": "Author", "content": "Rocco Caputo\nRocco Caputo is . POE is his brainchild. He wishes to thank you for your\ninterest, and he has more thanks than he can count for all the people who have contributed.\nPOE would not be nearly as cool without you.\n\nExcept where otherwise noted, POE is Copyright 1998-2013 Rocco Caputo. All rights reserved.\nPOE is free software; you may redistribute it and/or modify it under the same terms as Perl\nitself.\n\nThank you for reading!\n" } ] } }, "summary": "POE - portable multitasking and networking framework for any event loop", "flags": [], "examples": [], "see_also": [] }