ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/AnyEvent/lib/AnyEvent.pm
(Generate patch)

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.42 by root, Mon Apr 7 19:40:12 2008 UTC vs.
Revision 1.53 by root, Sat Apr 19 04:58:14 2008 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5Event, Coro, Glib, Tk, Perl - various supported event loops 5EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl - various supported event loops
6 6
7=head1 SYNOPSIS 7=head1 SYNOPSIS
8 8
9 use AnyEvent; 9 use AnyEvent;
10 10
14 14
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { 15 my $w = AnyEvent->timer (after => $seconds, cb => sub {
16 ... 16 ...
17 }); 17 });
18 18
19 my $w = AnyEvent->condvar; # stores wether a condition was flagged 19 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->wait; # enters "main loop" till $condvar gets ->broadcast 20 $w->wait; # enters "main loop" till $condvar gets ->broadcast
21 $w->broadcast; # wake up current and all future wait's 21 $w->broadcast; # wake up current and all future wait's
22 22
23=head1 WHY YOU SHOULD USE THIS MODULE 23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 24
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 26nowadays. So what is different about AnyEvent?
27 27
28Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of 28Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29policy> and AnyEvent is I<small and efficient>. 29policy> and AnyEvent is I<small and efficient>.
30 30
31First and foremost, I<AnyEvent is not an event model> itself, it only 31First and foremost, I<AnyEvent is not an event model> itself, it only
32interfaces to whatever event model the main program happens to use in a 32interfaces to whatever event model the main program happens to use in a
33pragmatic way. For event models and certain classes of immortals alike, 33pragmatic way. For event models and certain classes of immortals alike,
34the statement "there can only be one" is a bitter reality, and AnyEvent 34the statement "there can only be one" is a bitter reality: In general,
35helps hiding the differences. 35only one event loop can be active at the same time in a process. AnyEvent
36helps hiding the differences between those event loops.
36 37
37The goal of AnyEvent is to offer module authors the ability to do event 38The goal of AnyEvent is to offer module authors the ability to do event
38programming (waiting for I/O or timer events) without subscribing to a 39programming (waiting for I/O or timer events) without subscribing to a
39religion, a way of living, and most importantly: without forcing your 40religion, a way of living, and most importantly: without forcing your
40module users into the same thing by forcing them to use the same event 41module users into the same thing by forcing them to use the same event
41model you use. 42model you use.
42 43
43For modules like POE or IO::Async (which is actually doing all I/O 44For modules like POE or IO::Async (which is a total misnomer as it is
44I<synchronously>...), using them in your module is like joining a 45actually doing all I/O I<synchronously>...), using them in your module is
45cult: After you joined, you are dependent on them and you cannot use 46like joining a cult: After you joined, you are dependent on them and you
46anything else, as it is simply incompatible to everything that isn't 47cannot use anything else, as it is simply incompatible to everything that
47itself. 48isn't itself. What's worse, all the potential users of your module are
49I<also> forced to use the same event loop you use.
48 50
49AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk 51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
50works fine etc. etc. but none of these work together with the rest: POE 52fine. AnyEvent + Tk works fine etc. etc. but none of these work together
51+ IO::Async? no go. Tk + Event? no go. If your module uses one of 53with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if
52those, every user of your module has to use it, too. If your module 54your module uses one of those, every user of your module has to use it,
53uses AnyEvent, it works transparently with all event models it supports 55too. But if your module uses AnyEvent, it works transparently with all
54(including stuff like POE and IO::Async). 56event models it supports (including stuff like POE and IO::Async, as long
57as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof).
55 59
56In addition of being free of having to use I<the one and only true event 60In addition to being free of having to use I<the one and only true event
57model>, AnyEvent also is free of bloat and policy: with POE or similar 61model>, AnyEvent also is free of bloat and policy: with POE or similar
58modules, you get an enourmous amount of code and strict rules you have 62modules, you get an enourmous amount of code and strict rules you have to
59to follow. AnyEvent, on the other hand, is lean and to the point by only 63follow. AnyEvent, on the other hand, is lean and up to the point, by only
60offering the functionality that is useful, in as thin as a wrapper as 64offering the functionality that is necessary, in as thin as a wrapper as
61technically possible. 65technically possible.
66
67Of course, if you want lots of policy (this can arguably be somewhat
68useful) and you want to force your users to use the one and only event
69model, you should I<not> use this module.
62 70
63 71
64=head1 DESCRIPTION 72=head1 DESCRIPTION
65 73
66L<AnyEvent> provides an identical interface to multiple event loops. This 74L<AnyEvent> provides an identical interface to multiple event loops. This
67allows module authors to utilise an event loop without forcing module 75allows module authors to utilise an event loop without forcing module
68users to use the same event loop (as only a single event loop can coexist 76users to use the same event loop (as only a single event loop can coexist
69peacefully at any one time). 77peacefully at any one time).
70 78
71The interface itself is vaguely similar but not identical to the Event 79The interface itself is vaguely similar, but not identical to the L<Event>
72module. 80module.
73 81
74On the first call of any method, the module tries to detect the currently 82During the first call of any watcher-creation method, the module tries
75loaded event loop by probing wether any of the following modules is 83to detect the currently loaded event loop by probing whether one of the
76loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is 84following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,
77used. If none is found, the module tries to load these modules in the 85L<Event>, L<Glib>, L<Tk>. The first one found is used. If none are found,
78order given. The first one that could be successfully loaded will be 86the module tries to load these modules in the stated order. The first one
79used. If still none could be found, AnyEvent will fall back to a pure-perl 87that can be successfully loaded will be used. If, after this, still none
80event loop, which is also not very efficient. 88could be found, AnyEvent will fall back to a pure-perl event loop, which
89is not very efficient, but should work everywhere.
81 90
82Because AnyEvent first checks for modules that are already loaded, loading 91Because AnyEvent first checks for modules that are already loaded, loading
83an Event model explicitly before first using AnyEvent will likely make 92an event model explicitly before first using AnyEvent will likely make
84that model the default. For example: 93that model the default. For example:
85 94
86 use Tk; 95 use Tk;
87 use AnyEvent; 96 use AnyEvent;
88 97
89 # .. AnyEvent will likely default to Tk 98 # .. AnyEvent will likely default to Tk
99
100The I<likely> means that, if any module loads another event model and
101starts using it, all bets are off. Maybe you should tell their authors to
102use AnyEvent so their modules work together with others seamlessly...
90 103
91The pure-perl implementation of AnyEvent is called 104The pure-perl implementation of AnyEvent is called
92C<AnyEvent::Impl::Perl>. Like other event modules you can load it 105C<AnyEvent::Impl::Perl>. Like other event modules you can load it
93explicitly. 106explicitly.
94 107
97AnyEvent has the central concept of a I<watcher>, which is an object that 110AnyEvent has the central concept of a I<watcher>, which is an object that
98stores relevant data for each kind of event you are waiting for, such as 111stores relevant data for each kind of event you are waiting for, such as
99the callback to call, the filehandle to watch, etc. 112the callback to call, the filehandle to watch, etc.
100 113
101These watchers are normal Perl objects with normal Perl lifetime. After 114These watchers are normal Perl objects with normal Perl lifetime. After
102creating a watcher it will immediately "watch" for events and invoke 115creating a watcher it will immediately "watch" for events and invoke the
116callback when the event occurs (of course, only when the event model
117is in control).
118
103the callback. To disable the watcher you have to destroy it (e.g. by 119To disable the watcher you have to destroy it (e.g. by setting the
104setting the variable that stores it to C<undef> or otherwise deleting all 120variable you store it in to C<undef> or otherwise deleting all references
105references to it). 121to it).
106 122
107All watchers are created by calling a method on the C<AnyEvent> class. 123All watchers are created by calling a method on the C<AnyEvent> class.
108 124
125Many watchers either are used with "recursion" (repeating timers for
126example), or need to refer to their watcher object in other ways.
127
128An any way to achieve that is this pattern:
129
130 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
131 # you can use $w here, for example to undef it
132 undef $w;
133 });
134
135Note that C<my $w; $w => combination. This is necessary because in Perl,
136my variables are only visible after the statement in which they are
137declared.
138
109=head2 IO WATCHERS 139=head2 IO WATCHERS
110 140
111You can create I/O watcher by calling the C<< AnyEvent->io >> method with 141You can create an I/O watcher by calling the C<< AnyEvent->io >> method
112the following mandatory arguments: 142with the following mandatory key-value pairs as arguments:
113 143
114C<fh> the Perl I<filehandle> (not filedescriptor) to watch for 144C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for
115events. C<poll> must be a string that is either C<r> or C<w>, that creates 145events. C<poll> must be a string that is either C<r> or C<w>, which
116a watcher waiting for "r"eadable or "w"ritable events. C<cb> the callback 146creates a watcher waiting for "r"eadable or "w"ritable events,
117to invoke everytime the filehandle becomes ready. 147respectively. C<cb> is the callback to invoke each time the file handle
148becomes ready.
118 149
119Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on
120a socket you can have one r + one w, not any more (limitation comes from
121Tk - if you are sure you are not using Tk this limitation is gone).
122
123Filehandles will be kept alive, so as long as the watcher exists, the 150File handles will be kept alive, so as long as the watcher exists, the
124filehandle exists, too. 151file handle exists, too.
152
153It is not allowed to close a file handle as long as any watcher is active
154on the underlying file descriptor.
155
156Some event loops issue spurious readyness notifications, so you should
157always use non-blocking calls when reading/writing from/to your file
158handles.
125 159
126Example: 160Example:
127 161
128 # wait for readability of STDIN, then read a line and disable the watcher 162 # wait for readability of STDIN, then read a line and disable the watcher
129 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 163 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
135=head2 TIME WATCHERS 169=head2 TIME WATCHERS
136 170
137You can create a time watcher by calling the C<< AnyEvent->timer >> 171You can create a time watcher by calling the C<< AnyEvent->timer >>
138method with the following mandatory arguments: 172method with the following mandatory arguments:
139 173
140C<after> after how many seconds (fractions are supported) should the timer 174C<after> specifies after how many seconds (fractional values are
141activate. C<cb> the callback to invoke. 175supported) should the timer activate. C<cb> the callback to invoke in that
176case.
142 177
143The timer callback will be invoked at most once: if you want a repeating 178The timer callback will be invoked at most once: if you want a repeating
144timer you have to create a new watcher (this is a limitation by both Tk 179timer you have to create a new watcher (this is a limitation by both Tk
145and Glib). 180and Glib).
146 181
152 }); 187 });
153 188
154 # to cancel the timer: 189 # to cancel the timer:
155 undef $w; 190 undef $w;
156 191
192Example 2:
193
194 # fire an event after 0.5 seconds, then roughly every second
195 my $w;
196
197 my $cb = sub {
198 # cancel the old timer while creating a new one
199 $w = AnyEvent->timer (after => 1, cb => $cb);
200 };
201
202 # start the "loop" by creating the first watcher
203 $w = AnyEvent->timer (after => 0.5, cb => $cb);
204
205=head3 TIMING ISSUES
206
207There are two ways to handle timers: based on real time (relative, "fire
208in 10 seconds") and based on wallclock time (absolute, "fire at 12
209o'clock").
210
211While most event loops expect timers to specified in a relative way, they use
212absolute time internally. This makes a difference when your clock "jumps",
213for example, when ntp decides to set your clock backwards from the wrong 2014-01-01 to
2142008-01-01, a watcher that you created to fire "after" a second might actually take
215six years to finally fire.
216
217AnyEvent cannot compensate for this. The only event loop that is conscious
218about these issues is L<EV>, which offers both relative (ev_timer) and
219absolute (ev_periodic) timers.
220
221AnyEvent always prefers relative timers, if available, matching the
222AnyEvent API.
223
224=head2 SIGNAL WATCHERS
225
226You can watch for signals using a signal watcher, C<signal> is the signal
227I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
228be invoked whenever a signal occurs.
229
230Multiple signals occurances can be clumped together into one callback
231invocation, and callback invocation will be synchronous. synchronous means
232that it might take a while until the signal gets handled by the process,
233but it is guarenteed not to interrupt any other callbacks.
234
235The main advantage of using these watchers is that you can share a signal
236between multiple watchers.
237
238This watcher might use C<%SIG>, so programs overwriting those signals
239directly will likely not work correctly.
240
241Example: exit on SIGINT
242
243 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
244
245=head2 CHILD PROCESS WATCHERS
246
247You can also watch on a child process exit and catch its exit status.
248
249The child process is specified by the C<pid> argument (if set to C<0>, it
250watches for any child process exit). The watcher will trigger as often
251as status change for the child are received. This works by installing a
252signal handler for C<SIGCHLD>. The callback will be called with the pid
253and exit status (as returned by waitpid).
254
255Example: wait for pid 1333
256
257 my $w = AnyEvent->child (
258 pid => 1333,
259 cb => sub {
260 my ($pid, $status) = @_;
261 warn "pid $pid exited with status $status";
262 },
263 );
264
157=head2 CONDITION WATCHERS 265=head2 CONDITION VARIABLES
158 266
159Condition watchers can be created by calling the C<< AnyEvent->condvar >> 267Condition variables can be created by calling the C<< AnyEvent->condvar >>
160method without any arguments. 268method without any arguments.
161 269
162A condition watcher watches for a condition - precisely that the C<< 270A condition variable waits for a condition - precisely that the C<<
163->broadcast >> method has been called. 271->broadcast >> method has been called.
164 272
273They are very useful to signal that a condition has been fulfilled, for
274example, if you write a module that does asynchronous http requests,
275then a condition variable would be the ideal candidate to signal the
276availability of results.
277
278You can also use condition variables to block your main program until
279an event occurs - for example, you could C<< ->wait >> in your main
280program until the user clicks the Quit button in your app, which would C<<
281->broadcast >> the "quit" event.
282
165Note that condition watchers recurse into the event loop - if you have 283Note that condition variables recurse into the event loop - if you have
166two watchers that call C<< ->wait >> in a round-robbin fashion, you 284two pirces of code that call C<< ->wait >> in a round-robbin fashion, you
167lose. Therefore, condition watchers are good to export to your caller, but 285lose. Therefore, condition variables are good to export to your caller, but
168you should avoid making a blocking wait, at least in callbacks, as this 286you should avoid making a blocking wait yourself, at least in callbacks,
169usually asks for trouble. 287as this asks for trouble.
170 288
171The watcher has only two methods: 289This object has two methods:
172 290
173=over 4 291=over 4
174 292
175=item $cv->wait 293=item $cv->wait
176 294
177Wait (blocking if necessary) until the C<< ->broadcast >> method has been 295Wait (blocking if necessary) until the C<< ->broadcast >> method has been
178called on c<$cv>, while servicing other watchers normally. 296called on c<$cv>, while servicing other watchers normally.
179 297
180Not all event models support a blocking wait - some die in that case, so
181if you are using this from a module, never require a blocking wait, but
182let the caller decide wether the call will block or not (for example,
183by coupling condition variables with some kind of request results and
184supporting callbacks so the caller knows that getting the result will not
185block, while still suppporting blockign waits if the caller so desires).
186
187You can only wait once on a condition - additional calls will return 298You can only wait once on a condition - additional calls will return
188immediately. 299immediately.
189 300
301Not all event models support a blocking wait - some die in that case
302(programs might want to do that to stay interactive), so I<if you are
303using this from a module, never require a blocking wait>, but let the
304caller decide whether the call will block or not (for example, by coupling
305condition variables with some kind of request results and supporting
306callbacks so the caller knows that getting the result will not block,
307while still suppporting blocking waits if the caller so desires).
308
309Another reason I<never> to C<< ->wait >> in a module is that you cannot
310sensibly have two C<< ->wait >>'s in parallel, as that would require
311multiple interpreters or coroutines/threads, none of which C<AnyEvent>
312can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and
313L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
314from different coroutines, however).
315
190=item $cv->broadcast 316=item $cv->broadcast
191 317
192Flag the condition as ready - a running C<< ->wait >> and all further 318Flag the condition as ready - a running C<< ->wait >> and all further
193calls to C<wait> will return after this method has been called. If nobody 319calls to C<wait> will (eventually) return after this method has been
194is waiting the broadcast will be remembered.. 320called. If nobody is waiting the broadcast will be remembered..
321
322=back
195 323
196Example: 324Example:
197 325
198 # wait till the result is ready 326 # wait till the result is ready
199 my $result_ready = AnyEvent->condvar; 327 my $result_ready = AnyEvent->condvar;
200 328
201 # do something such as adding a timer 329 # do something such as adding a timer
202 # or socket watcher the calls $result_ready->broadcast 330 # or socket watcher the calls $result_ready->broadcast
203 # when the "result" is ready. 331 # when the "result" is ready.
332 # in this case, we simply use a timer:
333 my $w = AnyEvent->timer (
334 after => 1,
335 cb => sub { $result_ready->broadcast },
336 );
204 337
338 # this "blocks" (while handling events) till the watcher
339 # calls broadcast
205 $result_ready->wait; 340 $result_ready->wait;
206 341
207=back 342=head1 GLOBAL VARIABLES AND FUNCTIONS
208
209=head2 SIGNAL WATCHERS
210
211You can listen for signals using a signal watcher, C<signal> is the signal
212I<name> without any C<SIG> prefix. Multiple signals events can be clumped
213together into one callback invocation, and callback invocation might or
214might not be asynchronous.
215
216These watchers might use C<%SIG>, so programs overwriting those signals
217directly will likely not work correctly.
218
219Example: exit on SIGINT
220
221 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
222
223=head2 CHILD PROCESS WATCHERS
224
225You can also listen for the status of a child process specified by the
226C<pid> argument (or any child if the pid argument is 0). The watcher will
227trigger as often as status change for the child are received. This works
228by installing a signal handler for C<SIGCHLD>. The callback will be called with
229the pid and exit status (as returned by waitpid).
230
231Example: wait for pid 1333
232
233 my $w = AnyEvent->child (pid => 1333, cb => sub { warn "exit status $?" });
234
235=head1 GLOBALS
236 343
237=over 4 344=over 4
238 345
239=item $AnyEvent::MODEL 346=item $AnyEvent::MODEL
240 347
245AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 352AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
246 353
247The known classes so far are: 354The known classes so far are:
248 355
249 AnyEvent::Impl::CoroEV based on Coro::EV, best choice. 356 AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
357 AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
250 AnyEvent::Impl::EV based on EV (an interface to libev, also best choice). 358 AnyEvent::Impl::EV based on EV (an interface to libev, also best choice).
251 AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
252 AnyEvent::Impl::Event based on Event, also second best choice :) 359 AnyEvent::Impl::Event based on Event, also second best choice :)
253 AnyEvent::Impl::Glib based on Glib, second-best choice. 360 AnyEvent::Impl::Glib based on Glib, third-best choice.
254 AnyEvent::Impl::Tk based on Tk, very bad choice. 361 AnyEvent::Impl::Tk based on Tk, very bad choice.
255 AnyEvent::Impl::Perl pure-perl implementation, inefficient. 362 AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
256 363
257=item AnyEvent::detect 364=item AnyEvent::detect
258 365
259Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if 366Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
260necessary. You should only call this function right before you would have 367if necessary. You should only call this function right before you would
261created an AnyEvent watcher anyway, that is, very late at runtime. 368have created an AnyEvent watcher anyway, that is, as late as possible at
369runtime.
262 370
263=back 371=back
264 372
265=head1 WHAT TO DO IN A MODULE 373=head1 WHAT TO DO IN A MODULE
266 374
267As a module author, you should "use AnyEvent" and call AnyEvent methods 375As a module author, you should C<use AnyEvent> and call AnyEvent methods
268freely, but you should not load a specific event module or rely on it. 376freely, but you should not load a specific event module or rely on it.
269 377
270Be careful when you create watchers in the module body - Anyevent will 378Be careful when you create watchers in the module body - AnyEvent will
271decide which event module to use as soon as the first method is called, so 379decide which event module to use as soon as the first method is called, so
272by calling AnyEvent in your module body you force the user of your module 380by calling AnyEvent in your module body you force the user of your module
273to load the event module first. 381to load the event module first.
274 382
383Never call C<< ->wait >> on a condition variable unless you I<know> that
384the C<< ->broadcast >> method has been called on it already. This is
385because it will stall the whole program, and the whole point of using
386events is to stay interactive.
387
388It is fine, however, to call C<< ->wait >> when the user of your module
389requests it (i.e. if you create a http request object ad have a method
390called C<results> that returns the results, it should call C<< ->wait >>
391freely, as the user of your module knows what she is doing. always).
392
275=head1 WHAT TO DO IN THE MAIN PROGRAM 393=head1 WHAT TO DO IN THE MAIN PROGRAM
276 394
277There will always be a single main program - the only place that should 395There will always be a single main program - the only place that should
278dictate which event model to use. 396dictate which event model to use.
279 397
280If it doesn't care, it can just "use AnyEvent" and use it itself, or not 398If it doesn't care, it can just "use AnyEvent" and use it itself, or not
281do anything special and let AnyEvent decide which implementation to chose. 399do anything special (it does not need to be event-based) and let AnyEvent
400decide which implementation to chose if some module relies on it.
282 401
283If the main program relies on a specific event model (for example, in Gtk2 402If the main program relies on a specific event model. For example, in
284programs you have to rely on either Glib or Glib::Event), you should load 403Gtk2 programs you have to rely on the Glib module. You should load the
285it before loading AnyEvent or any module that uses it, generally, as early 404event module before loading AnyEvent or any module that uses it: generally
286as possible. The reason is that modules might create watchers when they 405speaking, you should load it as early as possible. The reason is that
287are loaded, and AnyEvent will decide on the event model to use as soon as 406modules might create watchers when they are loaded, and AnyEvent will
288it creates watchers, and it might chose the wrong one unless you load the 407decide on the event model to use as soon as it creates watchers, and it
289correct one yourself. 408might chose the wrong one unless you load the correct one yourself.
290 409
291You can chose to use a rather inefficient pure-perl implementation by 410You can chose to use a rather inefficient pure-perl implementation by
292loading the C<AnyEvent::Impl::Perl> module, but letting AnyEvent chose is 411loading the C<AnyEvent::Impl::Perl> module, which gives you similar
293generally better. 412behaviour everywhere, but letting AnyEvent chose is generally better.
294 413
295=cut 414=cut
296 415
297package AnyEvent; 416package AnyEvent;
298 417
299no warnings; 418no warnings;
300use strict; 419use strict;
301 420
302use Carp; 421use Carp;
303 422
304our $VERSION = '3.0'; 423our $VERSION = '3.11';
305our $MODEL; 424our $MODEL;
306 425
307our $AUTOLOAD; 426our $AUTOLOAD;
308our @ISA; 427our @ISA;
309 428
311 430
312our @REGISTRY; 431our @REGISTRY;
313 432
314my @models = ( 433my @models = (
315 [Coro::EV:: => AnyEvent::Impl::CoroEV::], 434 [Coro::EV:: => AnyEvent::Impl::CoroEV::],
435 [Coro::Event:: => AnyEvent::Impl::CoroEvent::],
316 [EV:: => AnyEvent::Impl::EV::], 436 [EV:: => AnyEvent::Impl::EV::],
317 [Coro::Event:: => AnyEvent::Impl::CoroEvent::],
318 [Event:: => AnyEvent::Impl::Event::], 437 [Event:: => AnyEvent::Impl::Event::],
319 [Glib:: => AnyEvent::Impl::Glib::], 438 [Glib:: => AnyEvent::Impl::Glib::],
320 [Tk:: => AnyEvent::Impl::Tk::], 439 [Tk:: => AnyEvent::Impl::Tk::],
321 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 440 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
322); 441);
473 undef $CHLD_W unless keys %PID_CB; 592 undef $CHLD_W unless keys %PID_CB;
474} 593}
475 594
476=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 595=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
477 596
597This is an advanced topic that you do not normally need to use AnyEvent in
598a module. This section is only of use to event loop authors who want to
599provide AnyEvent compatibility.
600
478If you need to support another event library which isn't directly 601If you need to support another event library which isn't directly
479supported by AnyEvent, you can supply your own interface to it by 602supported by AnyEvent, you can supply your own interface to it by
480pushing, before the first watcher gets created, the package name of 603pushing, before the first watcher gets created, the package name of
481the event module and the package name of the interface to use onto 604the event module and the package name of the interface to use onto
482C<@AnyEvent::REGISTRY>. You can do that before and even without loading 605C<@AnyEvent::REGISTRY>. You can do that before and even without loading
483AnyEvent. 606AnyEvent, so it is reasonably cheap.
484 607
485Example: 608Example:
486 609
487 push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; 610 push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
488 611
489This tells AnyEvent to (literally) use the C<urxvt::anyevent::> 612This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
490package/class when it finds the C<urxvt> package/module is loaded. When 613package/class when it finds the C<urxvt> package/module is already loaded.
614
491AnyEvent is loaded and asked to find a suitable event model, it will 615When AnyEvent is loaded and asked to find a suitable event model, it
492first check for the presence of urxvt. 616will first check for the presence of urxvt by trying to C<use> the
617C<urxvt::anyevent> module.
493 618
494The class should provide implementations for all watcher types (see 619The class should provide implementations for all watcher types. See
495L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib> 620L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code)
496(Source code) and so on for actual examples, use C<perldoc -m 621and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to
497AnyEvent::Impl::Glib> to see the sources). 622see the sources.
498 623
624If you don't provide C<signal> and C<child> watchers than AnyEvent will
625provide suitable (hopefully) replacements.
626
499The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) 627The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)
500uses the above line as-is. An interface isn't included in AnyEvent 628terminal emulator uses the above line as-is. An interface isn't included
501because it doesn't make sense outside the embedded interpreter inside 629in AnyEvent because it doesn't make sense outside the embedded interpreter
502I<rxvt-unicode>, and it is updated and maintained as part of the 630inside I<rxvt-unicode>, and it is updated and maintained as part of the
503I<rxvt-unicode> distribution. 631I<rxvt-unicode> distribution.
504 632
505I<rxvt-unicode> also cheats a bit by not providing blocking access to 633I<rxvt-unicode> also cheats a bit by not providing blocking access to
506condition variables: code blocking while waiting for a condition will 634condition variables: code blocking while waiting for a condition will
507C<die>. This still works with most modules/usages, and blocking calls must 635C<die>. This still works with most modules/usages, and blocking calls must
508not be in an interactive application, so it makes sense. 636not be done in an interactive application, so it makes sense.
509 637
510=head1 ENVIRONMENT VARIABLES 638=head1 ENVIRONMENT VARIABLES
511 639
512The following environment variables are used by this module: 640The following environment variables are used by this module:
513 641
514C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event 642C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, cause AnyEvent to
515model gets used. 643report to STDERR which event model it chooses.
516 644
517=head1 EXAMPLE 645=head1 EXAMPLE PROGRAM
518 646
519The following program uses an io watcher to read data from stdin, a timer 647The following program uses an IO watcher to read data from STDIN, a timer
520to display a message once per second, and a condvar to exit the program 648to display a message once per second, and a condition variable to quit the
521when the user enters quit: 649program when the user enters quit:
522 650
523 use AnyEvent; 651 use AnyEvent;
524 652
525 my $cv = AnyEvent->condvar; 653 my $cv = AnyEvent->condvar;
526 654
527 my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 655 my $io_watcher = AnyEvent->io (
656 fh => \*STDIN,
657 poll => 'r',
658 cb => sub {
528 warn "io event <$_[0]>\n"; # will always output <r> 659 warn "io event <$_[0]>\n"; # will always output <r>
529 chomp (my $input = <STDIN>); # read a line 660 chomp (my $input = <STDIN>); # read a line
530 warn "read: $input\n"; # output what has been read 661 warn "read: $input\n"; # output what has been read
531 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 662 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i
663 },
532 }); 664 );
533 665
534 my $time_watcher; # can only be used once 666 my $time_watcher; # can only be used once
535 667
536 sub new_timer { 668 sub new_timer {
537 $timer = AnyEvent->timer (after => 1, cb => sub { 669 $timer = AnyEvent->timer (after => 1, cb => sub {
619 $txn->{finished}->wait; 751 $txn->{finished}->wait;
620 return $txn->{result}; 752 return $txn->{result};
621 753
622The actual code goes further and collects all errors (C<die>s, exceptions) 754The actual code goes further and collects all errors (C<die>s, exceptions)
623that occured during request processing. The C<result> method detects 755that occured during request processing. The C<result> method detects
624wether an exception as thrown (it is stored inside the $txn object) 756whether an exception as thrown (it is stored inside the $txn object)
625and just throws the exception, which means connection errors and other 757and just throws the exception, which means connection errors and other
626problems get reported tot he code that tries to use the result, not in a 758problems get reported tot he code that tries to use the result, not in a
627random callback. 759random callback.
628 760
629All of this enables the following usage styles: 761All of this enables the following usage styles:
630 762
6311. Blocking: 7631. Blocking:
632 764
633 my $data = $fcp->client_get ($url); 765 my $data = $fcp->client_get ($url);
634 766
6352. Blocking, but parallelizing: 7672. Blocking, but running in parallel:
636 768
637 my @datas = map $_->result, 769 my @datas = map $_->result,
638 map $fcp->txn_client_get ($_), 770 map $fcp->txn_client_get ($_),
639 @urls; 771 @urls;
640 772
641Both blocking examples work without the module user having to know 773Both blocking examples work without the module user having to know
642anything about events. 774anything about events.
643 775
6443a. Event-based in a main program, using any support Event module: 7763a. Event-based in a main program, using any supported event module:
645 777
646 use Event; 778 use EV;
647 779
648 $fcp->txn_client_get ($url)->cb (sub { 780 $fcp->txn_client_get ($url)->cb (sub {
649 my $txn = shift; 781 my $txn = shift;
650 my $data = $txn->result; 782 my $data = $txn->result;
651 ... 783 ...
652 }); 784 });
653 785
654 Event::loop; 786 EV::loop;
655 787
6563b. The module user could use AnyEvent, too: 7883b. The module user could use AnyEvent, too:
657 789
658 use AnyEvent; 790 use AnyEvent;
659 791
666 798
667 $quit->wait; 799 $quit->wait;
668 800
669=head1 SEE ALSO 801=head1 SEE ALSO
670 802
671Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>. 803Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,
804L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>.
672 805
673Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>. 806Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,
807L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>,
808L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>.
674 809
675Nontrivial usage example: L<Net::FCP>. 810Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
676 811
677=head1 812=head1
678 813
679=cut 814=cut
680 815

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines