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Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC vs.
Revision 1.78 by root, Sat Dec 22 11:50:04 2007 UTC

88@EV::Fork::ISA = 88@EV::Fork::ISA =
89 "EV::Watcher"; 89 "EV::Watcher";
90 90
91@EV::Loop::Default::ISA = "EV::Loop"; 91@EV::Loop::Default::ISA = "EV::Loop";
92 92
93=head1 EVENT LOOPS
94
95EV supports multiple event loops: There is a single "default event loop"
96that can handle everything including signals and child watchers, and any
97number of "dynamic event loops" that can use different backends (with
98various limitations), but no child and signal watchers.
99
100You do not have to do anything to create the default event loop: When
101the module is loaded a suitable backend is selected on the premise of
102selecting a working backend (which for example rules out kqueue on most
103BSDs). Modules should, unless they have "special needs" always use the
104default loop as this is fastest (perl-wise), best supported by other
105modules (e.g. AnyEvent or Coro) and most portable event loop.
106
107For specific programs you cna create additional event loops dynamically.
108
109=over 4
110
111=item $loop = new EV::loop [$flags]
112
113Create a new event loop as per the specified flags. Please refer to the
114C<ev_loop_new ()> function description in the libev documentation
115(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
116for more info.
117
118The loop will automatically be destroyed when it is no longer referenced
119by any watcher and the loop object goes out of scope.
120
121Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
122is protected by this module.
123
124=item $loop->loop_fork
125
126Must be called after a fork in the child, before entering or continuing
127the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
128this fucntion automatically, at some performance loss (refer to the libev
129documentation).
130
131=back
132
133
93=head1 BASIC INTERFACE 134=head1 BASIC INTERFACE
94 135
95=over 4 136=over 4
96 137
97=item $EV::DIED 138=item $EV::DIED
106 147
107Returns the current time in (fractional) seconds since the epoch. 148Returns the current time in (fractional) seconds since the epoch.
108 149
109=item $time = EV::now 150=item $time = EV::now
110 151
152=item $time = $loop->now
153
111Returns the time the last event loop iteration has been started. This 154Returns the time the last event loop iteration has been started. This
112is the time that (relative) timers are based on, and refering to it is 155is the time that (relative) timers are based on, and refering to it is
113usually faster then calling EV::time. 156usually faster then calling EV::time.
114 157
115=item $method = EV::method 158=item $backend = EV::backend
159
160=item $backend = $loop->backend
116 161
117Returns an integer describing the backend used by libev (EV::METHOD_SELECT 162Returns an integer describing the backend used by libev (EV::METHOD_SELECT
118or EV::METHOD_EPOLL). 163or EV::METHOD_EPOLL).
119 164
120=item EV::loop [$flags] 165=item EV::loop [$flags]
166
167=item $loop->loop ([$flags])
121 168
122Begin checking for events and calling callbacks. It returns when a 169Begin checking for events and calling callbacks. It returns when a
123callback calls EV::unloop. 170callback calls EV::unloop.
124 171
125The $flags argument can be one of the following: 172The $flags argument can be one of the following:
128 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 175 EV::LOOP_ONESHOT block at most once (wait, but do not loop)
129 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 176 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
130 177
131=item EV::unloop [$how] 178=item EV::unloop [$how]
132 179
180=item $loop->unloop ([$how])
181
133When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 182When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
134innermost call to EV::loop return. 183innermost call to EV::loop return.
135 184
136When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 185When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
137fast as possible. 186fast as possible.
138 187
139=item $count = EV::loop_count 188=item $count = EV::loop_count
140 189
190=item $count = $loop->loop_count
191
141Return the number of times the event loop has polled for new 192Return the number of times the event loop has polled for new
142events. Sometiems useful as a generation counter. 193events. Sometiems useful as a generation counter.
143 194
144=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 195=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
196
197=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
145 198
146This function rolls together an I/O and a timer watcher for a single 199This function rolls together an I/O and a timer watcher for a single
147one-shot event without the need for managing a watcher object. 200one-shot event without the need for managing a watcher object.
148 201
149If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> 202If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
155If timeout is C<undef> or negative, then there will be no 208If timeout is C<undef> or negative, then there will be no
156timeout. Otherwise a EV::timer with this value will be started. 209timeout. Otherwise a EV::timer with this value will be started.
157 210
158When an error occurs or either the timeout or I/O watcher triggers, then 211When an error occurs or either the timeout or I/O watcher triggers, then
159the callback will be called with the received event set (in general 212the callback will be called with the received event set (in general
160you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, 213you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
161C<EV::WRITE> and C<EV::TIMEOUT>). 214C<EV::WRITE> and C<EV::TIMEOUT>).
162 215
163EV::once doesn't return anything: the watchers stay active till either 216EV::once doesn't return anything: the watchers stay active till either
164of them triggers, then they will be stopped and freed, and the callback 217of them triggers, then they will be stopped and freed, and the callback
165invoked. 218invoked.
166 219
167=item EV::feed_fd_event ($fd, $revents) 220=item EV::feed_fd_event ($fd, $revents)
168 221
222=item $loop->feed_fd_event ($fd, $revents)
223
169Feed an event on a file descriptor into EV. EV will react to this call as 224Feed an event on a file descriptor into EV. EV will react to this call as
170if the readyness notifications specified by C<$revents> (a combination of 225if the readyness notifications specified by C<$revents> (a combination of
171C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 226C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
172 227
173=item EV::feed_signal_event ($signal) 228=item EV::feed_signal_event ($signal)
176specified by C<$signal> had occured. 231specified by C<$signal> had occured.
177 232
178=back 233=back
179 234
180 235
181=head2 WATCHER OBJECTS 236=head1 WATCHER OBJECTS
182 237
183A watcher is an object that gets created to record your interest in some 238A watcher is an object that gets created to record your interest in some
184event. For instance, if you want to wait for STDIN to become readable, you 239event. For instance, if you want to wait for STDIN to become readable, you
185would create an EV::io watcher for that: 240would create an EV::io watcher for that:
186 241
187 my $watcher = EV::io *STDIN, EV::READ, sub { 242 my $watcher = EV::io *STDIN, EV::READ, sub {
188 my ($watcher, $revents) = @_; 243 my ($watcher, $revents) = @_;
189 warn "yeah, STDIN should not be readable without blocking!\n" 244 warn "yeah, STDIN should now be readable without blocking!\n"
190 }; 245 };
191 246
192All watchers can be active (waiting for events) or inactive (paused). Only 247All watchers can be active (waiting for events) or inactive (paused). Only
193active watchers will have their callbacks invoked. All callbacks will be 248active watchers will have their callbacks invoked. All callbacks will be
194called with at least two arguments: the watcher and a bitmask of received 249called with at least two arguments: the watcher and a bitmask of received
278Feed some events on this watcher into EV. EV will react to this call as if 333Feed some events on this watcher into EV. EV will react to this call as if
279the watcher had received the given C<$revents> mask. 334the watcher had received the given C<$revents> mask.
280 335
281=item $revents = $w->clear_pending 336=item $revents = $w->clear_pending
282 337
283If the watcher is pending, this function returns clears its pending status 338If the watcher is pending, this function clears its pending status and
284and returns its C<$revents> bitset (as if its callback was invoked). If the 339returns its C<$revents> bitset (as if its callback was invoked). If the
285watcher isn't pending it does nothing and returns C<0>. 340watcher isn't pending it does nothing and returns C<0>.
286 341
287=item $previous_state = $w->keepalive ($bool) 342=item $previous_state = $w->keepalive ($bool)
288 343
289Normally, C<EV::loop> will return when there are no active watchers 344Normally, C<EV::loop> will return when there are no active watchers
290(which is a "deadlock" because no progress can be made anymore). This is 345(which is a "deadlock" because no progress can be made anymore). This is
291convinient because it allows you to start your watchers (and your jobs), 346convinient because it allows you to start your watchers (and your jobs),
292call C<EV::loop> once and when it returns you know that all your jobs are 347call C<EV::loop> once and when it returns you know that all your jobs are
293finished (or they forgot to register some watchers for their task :). 348finished (or they forgot to register some watchers for their task :).
294 349
295Sometimes, however, this gets in your way, for example when you the module 350Sometimes, however, this gets in your way, for example when the module
296that calls C<EV::loop> (usually the main program) is not the same module 351that calls C<EV::loop> (usually the main program) is not the same module
297as a long-living watcher (for example a DNS client module written by 352as a long-living watcher (for example a DNS client module written by
298somebody else even). Then you might want any outstanding requests to be 353somebody else even). Then you might want any outstanding requests to be
299handled, but you would not want to keep C<EV::loop> from returning just 354handled, but you would not want to keep C<EV::loop> from returning just
300because you happen to have this long-running UDP port watcher. 355because you happen to have this long-running UDP port watcher.
308Example: Register an I/O watcher for some UDP socket but do not keep the 363Example: Register an I/O watcher for some UDP socket but do not keep the
309event loop from running just because of that watcher. 364event loop from running just because of that watcher.
310 365
311 my $udp_socket = ... 366 my $udp_socket = ...
312 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 367 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
313 $udp_watcher->keepalive (0); 368 $1000udp_watcher->keepalive (0);
314 369
315=back 370=item $loop = $w->loop
316 371
372Return the loop that this watcher is attached to.
317 373
374=back
375
376
318=head2 WATCHER TYPES 377=head1 WATCHER TYPES
319 378
320Each of the following subsections describes a single watcher type. 379Each of the following subsections describes a single watcher type.
321 380
322=head3 I/O WATCHERS - is this file descriptor readable or writable? 381=head3 I/O WATCHERS - is this file descriptor readable or writable?
323 382
324=over 4 383=over 4
325 384
326=item $w = EV::io $fileno_or_fh, $eventmask, $callback 385=item $w = EV::io $fileno_or_fh, $eventmask, $callback
327 386
328=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback 387=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
388
389=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
390
391=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
329 392
330As long as the returned watcher object is alive, call the C<$callback> 393As long as the returned watcher object is alive, call the C<$callback>
331when at least one of events specified in C<$eventmask> occurs. 394when at least one of events specified in C<$eventmask> occurs.
332 395
333The $eventmask can be one or more of these constants ORed together: 396The $eventmask can be one or more of these constants ORed together:
362=over 4 425=over 4
363 426
364=item $w = EV::timer $after, $repeat, $callback 427=item $w = EV::timer $after, $repeat, $callback
365 428
366=item $w = EV::timer_ns $after, $repeat, $callback 429=item $w = EV::timer_ns $after, $repeat, $callback
430
431=item $w = $loop->timer ($after, $repeat, $callback)
432
433=item $w = $loop->timer_ns ($after, $repeat, $callback)
367 434
368Calls the callback after C<$after> seconds (which may be fractional). If 435Calls the callback after C<$after> seconds (which may be fractional). If
369C<$repeat> is non-zero, the timer will be restarted (with the $repeat 436C<$repeat> is non-zero, the timer will be restarted (with the $repeat
370value as $after) after the callback returns. 437value as $after) after the callback returns.
371 438
412=over 4 479=over 4
413 480
414=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback 481=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
415 482
416=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 483=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
484
485=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
486
487=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
417 488
418Similar to EV::timer, but is not based on relative timeouts but on 489Similar to EV::timer, but is not based on relative timeouts but on
419absolute times. Apart from creating "simple" timers that trigger "at" the 490absolute times. Apart from creating "simple" timers that trigger "at" the
420specified time, it can also be used for non-drifting absolute timers and 491specified time, it can also be used for non-drifting absolute timers and
421more complex, cron-like, setups that are not adversely affected by time 492more complex, cron-like, setups that are not adversely affected by time
546 617
547=item $w = EV::child $pid, $callback 618=item $w = EV::child $pid, $callback
548 619
549=item $w = EV::child_ns $pid, $callback 620=item $w = EV::child_ns $pid, $callback
550 621
622=item $w = $loop->child ($pid, $callback)
623
624=item $w = $loop->child_ns ($pid, $callback)
625
551Call the callback when a status change for pid C<$pid> (or any pid if 626Call the callback when a status change for pid C<$pid> (or any pid if
552C<$pid> is 0) has been received. More precisely: when the process receives 627C<$pid> is 0) has been received. More precisely: when the process receives
553a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all 628a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
554changed/zombie children and call the callback. 629changed/zombie children and call the callback.
555 630
596 671
597=item $w = EV::stat $path, $interval, $callback 672=item $w = EV::stat $path, $interval, $callback
598 673
599=item $w = EV::stat_ns $path, $interval, $callback 674=item $w = EV::stat_ns $path, $interval, $callback
600 675
676=item $w = $loop->stat ($path, $interval, $callback)
677
678=item $w = $loop->stat_ns ($path, $interval, $callback)
679
601Call the callback when a file status change has been detected on 680Call the callback when a file status change has been detected on
602C<$path>. The C<$path> does not need to exist, changing from "path exists" 681C<$path>. The C<$path> does not need to exist, changing from "path exists"
603to "path does not exist" is a status change like any other. 682to "path does not exist" is a status change like any other.
604 683
605The C<$interval> is a recommended polling interval for systems where 684The C<$interval> is a recommended polling interval for systems where
674=over 4 753=over 4
675 754
676=item $w = EV::idle $callback 755=item $w = EV::idle $callback
677 756
678=item $w = EV::idle_ns $callback 757=item $w = EV::idle_ns $callback
758
759=item $w = $loop->idle ($callback)
760
761=item $w = $loop->idle_ns ($callback)
679 762
680Call the callback when there are no other pending watchers of the same or 763Call the callback when there are no other pending watchers of the same or
681higher priority (excluding check, prepare and other idle watchers of the 764higher priority (excluding check, prepare and other idle watchers of the
682same or lower priority, of course). They are called idle watchers because 765same or lower priority, of course). They are called idle watchers because
683when the watcher is the highest priority pending event in the process, the 766when the watcher is the highest priority pending event in the process, the
706 789
707=item $w = EV::prepare $callback 790=item $w = EV::prepare $callback
708 791
709=item $w = EV::prepare_ns $callback 792=item $w = EV::prepare_ns $callback
710 793
794=item $w = $loop->prepare ($callback)
795
796=item $w = $loop->prepare_ns ($callback)
797
711Call the callback just before the process would block. You can still 798Call the callback just before the process would block. You can still
712create/modify any watchers at this point. 799create/modify any watchers at this point.
713 800
714See the EV::check watcher, below, for explanations and an example. 801See the EV::check watcher, below, for explanations and an example.
715 802
723=over 4 810=over 4
724 811
725=item $w = EV::check $callback 812=item $w = EV::check $callback
726 813
727=item $w = EV::check_ns $callback 814=item $w = EV::check_ns $callback
815
816=item $w = $loop->check ($callback)
817
818=item $w = $loop->check_ns ($callback)
728 819
729Call the callback just after the process wakes up again (after it has 820Call the callback just after the process wakes up again (after it has
730gathered events), but before any other callbacks have been invoked. 821gathered events), but before any other callbacks have been invoked.
731 822
732This is used to integrate other event-based software into the EV 823This is used to integrate other event-based software into the EV
787 878
788=item $w = EV::fork $callback 879=item $w = EV::fork $callback
789 880
790=item $w = EV::fork_ns $callback 881=item $w = EV::fork_ns $callback
791 882
883=item $w = $loop->fork ($callback)
884
885=item $w = $loop->fork_ns ($callback)
886
792Call the callback before the event loop is resumed in the child process 887Call the callback before the event loop is resumed in the child process
793after a fork. 888after a fork.
794 889
795The C<fork_ns> variant doesn't start (activate) the newly created watcher. 890The C<fork_ns> variant doesn't start (activate) the newly created watcher.
796 891
811to be called on every event loop iteration by installing a C<EV::check> 906to be called on every event loop iteration by installing a C<EV::check>
812watcher: 907watcher:
813 908
814 my $async_check = EV::check sub { }; 909 my $async_check = EV::check sub { };
815 910
816This ensures that perl shortly gets into control for a short time, and 911This ensures that perl gets into control for a short time to handle any
817also ensures slower overall operation. 912pending signals, and also ensures (slightly) slower overall operation.
818 913
819=head1 THREADS 914=head1 THREADS
820 915
821Threads are not supported by this module in any way. Perl pseudo-threads 916Threads are not supported by this module in any way. Perl pseudo-threads
822is evil stuff and must die. As soon as Perl gains real threads I will work 917is evil stuff and must die. As soon as Perl gains real threads I will work
850 945
8511; 9461;
852 947
853=head1 SEE ALSO 948=head1 SEE ALSO
854 949
855L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as 950L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
856event loop), L<Coro::EV> (efficient coroutines with EV). 951event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
952coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
857 953
858=head1 AUTHOR 954=head1 AUTHOR
859 955
860 Marc Lehmann <schmorp@schmorp.de> 956 Marc Lehmann <schmorp@schmorp.de>
861 http://home.schmorp.de/ 957 http://home.schmorp.de/

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