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58 | This module provides an interface to libev |
58 | This module provides an interface to libev |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
60 | below is comprehensive, one might also consult the documentation of libev |
60 | below is comprehensive, one might also consult the documentation of libev |
61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
62 | watcher semantics or some discussion on the available backends, or how to |
62 | watcher semantics or some discussion on the available backends, or how to |
63 | force a specific backend with C<LIBEV_FLAGS>. |
63 | force a specific backend with C<LIBEV_FLAGS>, or just about in any case |
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64 | because it has much more detailed information. |
64 | |
65 | |
65 | =cut |
66 | =cut |
66 | |
67 | |
67 | package EV; |
68 | package EV; |
68 | |
69 | |
69 | use strict; |
70 | use strict; |
70 | |
71 | |
71 | BEGIN { |
72 | BEGIN { |
72 | our $VERSION = '1.6'; |
73 | our $VERSION = '1.72'; |
73 | use XSLoader; |
74 | use XSLoader; |
74 | XSLoader::load "EV", $VERSION; |
75 | XSLoader::load "EV", $VERSION; |
75 | } |
76 | } |
76 | |
77 | |
77 | @EV::IO::ISA = |
78 | @EV::IO::ISA = |
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92 | =over 4 |
93 | =over 4 |
93 | |
94 | |
94 | =item $EV::DIED |
95 | =item $EV::DIED |
95 | |
96 | |
96 | Must contain a reference to a function that is called when a callback |
97 | Must contain a reference to a function that is called when a callback |
97 | throws an exception (with $@ containing thr error). The default prints an |
98 | throws an exception (with $@ containing the error). The default prints an |
98 | informative message and continues. |
99 | informative message and continues. |
99 | |
100 | |
100 | If this callback throws an exception it will be silently ignored. |
101 | If this callback throws an exception it will be silently ignored. |
101 | |
102 | |
102 | =item $time = EV::time |
103 | =item $time = EV::time |
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159 | |
160 | |
160 | EV::once doesn't return anything: the watchers stay active till either |
161 | EV::once doesn't return anything: the watchers stay active till either |
161 | of them triggers, then they will be stopped and freed, and the callback |
162 | of them triggers, then they will be stopped and freed, and the callback |
162 | invoked. |
163 | invoked. |
163 | |
164 | |
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165 | =item EV::feed_fd_event ($fd, $revents) |
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166 | |
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167 | Feed an event on a file descriptor into EV. EV will react to this call as |
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168 | if the readyness notifications specified by C<$revents> (a combination of |
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169 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
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170 | |
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171 | =item EV::feed_signal_event ($signal) |
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172 | |
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173 | Feed a signal event into EV. EV will react to this call as if the signal |
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174 | specified by C<$signal> had occured. |
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175 | |
164 | =back |
176 | =back |
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177 | |
165 | |
178 | |
166 | =head2 WATCHER OBJECTS |
179 | =head2 WATCHER OBJECTS |
167 | |
180 | |
168 | A watcher is an object that gets created to record your interest in some |
181 | A watcher is an object that gets created to record your interest in some |
169 | event. For instance, if you want to wait for STDIN to become readable, you |
182 | event. For instance, if you want to wait for STDIN to become readable, you |
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180 | events. |
193 | events. |
181 | |
194 | |
182 | Each watcher type has its associated bit in revents, so you can use the |
195 | Each watcher type has its associated bit in revents, so you can use the |
183 | same callback for multiple watchers. The event mask is named after the |
196 | same callback for multiple watchers. The event mask is named after the |
184 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
197 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
185 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
198 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
186 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
199 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
187 | uses EV::TIMEOUT). |
200 | uses EV::TIMEOUT). |
188 | |
201 | |
189 | In the rare case where one wants to create a watcher but not start it at |
202 | In the rare case where one wants to create a watcher but not start it at |
190 | the same time, each constructor has a variant with a trailing C<_ns> in |
203 | the same time, each constructor has a variant with a trailing C<_ns> in |
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212 | |
225 | |
213 | =item $w->stop |
226 | =item $w->stop |
214 | |
227 | |
215 | Stop a watcher if it is active. Also clear any pending events (events that |
228 | Stop a watcher if it is active. Also clear any pending events (events that |
216 | have been received but that didn't yet result in a callback invocation), |
229 | have been received but that didn't yet result in a callback invocation), |
217 | regardless of wether the watcher was active or not. |
230 | regardless of whether the watcher was active or not. |
218 | |
231 | |
219 | =item $bool = $w->is_active |
232 | =item $bool = $w->is_active |
220 | |
233 | |
221 | Returns true if the watcher is active, false otherwise. |
234 | Returns true if the watcher is active, false otherwise. |
222 | |
235 | |
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252 | The default priority of any newly-created watcher is 0. |
265 | The default priority of any newly-created watcher is 0. |
253 | |
266 | |
254 | Note that the priority semantics have not yet been fleshed out and are |
267 | Note that the priority semantics have not yet been fleshed out and are |
255 | subject to almost certain change. |
268 | subject to almost certain change. |
256 | |
269 | |
257 | =item $w->trigger ($revents) |
270 | =item $w->invoke ($revents) |
258 | |
271 | |
259 | Call the callback *now* with the given event mask. |
272 | Call the callback *now* with the given event mask. |
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273 | |
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274 | =item $w->feed_event ($revents) |
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275 | |
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276 | Feed some events on this watcher into EV. EV will react to this call as if |
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277 | the watcher had received the given C<$revents> mask. |
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278 | |
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279 | =item $revents = $w->clear_pending |
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280 | |
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281 | If the watcher is pending, this function returns clears its pending status |
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282 | and returns its C<$revents> bitset (as if its callback was invoked). If the |
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283 | watcher isn't pending it does nothing and returns C<0>. |
260 | |
284 | |
261 | =item $previous_state = $w->keepalive ($bool) |
285 | =item $previous_state = $w->keepalive ($bool) |
262 | |
286 | |
263 | Normally, C<EV::loop> will return when there are no active watchers |
287 | Normally, C<EV::loop> will return when there are no active watchers |
264 | (which is a "deadlock" because no progress can be made anymore). This is |
288 | (which is a "deadlock" because no progress can be made anymore). This is |
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277 | though your watcher is active, it won't keep C<EV::loop> from returning. |
301 | though your watcher is active, it won't keep C<EV::loop> from returning. |
278 | |
302 | |
279 | The initial value for keepalive is true (enabled), and you cna change it |
303 | The initial value for keepalive is true (enabled), and you cna change it |
280 | any time. |
304 | any time. |
281 | |
305 | |
282 | Example: Register an IO watcher for some UDP socket but do not keep the |
306 | Example: Register an I/O watcher for some UDP socket but do not keep the |
283 | event loop from running just because of that watcher. |
307 | event loop from running just because of that watcher. |
284 | |
308 | |
285 | my $udp_socket = ... |
309 | my $udp_socket = ... |
286 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
310 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
287 | $udp_watcher->keepalive (0); |
311 | $udp_watcher->keepalive (0); |
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291 | |
315 | |
292 | =head2 WATCHER TYPES |
316 | =head2 WATCHER TYPES |
293 | |
317 | |
294 | Each of the following subsections describes a single watcher type. |
318 | Each of the following subsections describes a single watcher type. |
295 | |
319 | |
296 | =head3 IO WATCHERS - is this file descriptor readable or writable? |
320 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
297 | |
321 | |
298 | =over 4 |
322 | =over 4 |
299 | |
323 | |
300 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
324 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
301 | |
325 | |
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645 | |
669 | |
646 | =item $w = EV::idle $callback |
670 | =item $w = EV::idle $callback |
647 | |
671 | |
648 | =item $w = EV::idle_ns $callback |
672 | =item $w = EV::idle_ns $callback |
649 | |
673 | |
650 | Call the callback when there are no pending io, timer/periodic, signal or |
674 | Call the callback when there are no other pending watchers of the same or |
651 | child events, i.e. when the process is idle. |
675 | higher priority (excluding check, prepare and other idle watchers of the |
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676 | same or lower priority, of course). They are called idle watchers because |
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677 | when the watcher is the highest priority pending event in the process, the |
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678 | process is considered to be idle at that priority. |
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679 | |
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680 | If you want a watcher that is only ever called when I<no> other events are |
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681 | outstanding you have to set the priority to C<EV::MINPRI>. |
652 | |
682 | |
653 | The process will not block as long as any idle watchers are active, and |
683 | The process will not block as long as any idle watchers are active, and |
654 | they will be called repeatedly until stopped. |
684 | they will be called repeatedly until stopped. |
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685 | |
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686 | For example, if you have idle watchers at priority C<0> and C<1>, and |
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687 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
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688 | and the I/O watcher will always run when ready. Only when the idle watcher |
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689 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
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690 | pending with the C<0>-priority idle watcher be invoked. |
655 | |
691 | |
656 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
692 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
657 | |
693 | |
658 | =back |
694 | =back |
659 | |
695 | |
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700 | or return; |
736 | or return; |
701 | |
737 | |
702 | # make the dispatcher handle any outstanding stuff |
738 | # make the dispatcher handle any outstanding stuff |
703 | ... not shown |
739 | ... not shown |
704 | |
740 | |
705 | # create an IO watcher for each and every socket |
741 | # create an I/O watcher for each and every socket |
706 | @snmp_watcher = ( |
742 | @snmp_watcher = ( |
707 | (map { EV::io $_, EV::READ, sub { } } |
743 | (map { EV::io $_, EV::READ, sub { } } |
708 | keys %{ $dispatcher->{_descriptors} }), |
744 | keys %{ $dispatcher->{_descriptors} }), |
709 | |
745 | |
710 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
746 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
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752 | |
788 | |
753 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
789 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
754 | |
790 | |
755 | =back |
791 | =back |
756 | |
792 | |
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793 | |
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794 | =head1 PERL SIGNALS |
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795 | |
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796 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
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797 | with EV is as the same as any other C library: Perl-signals will only be |
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798 | handled when Perl runs, which means your signal handler might be invoked |
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799 | only the next time an event callback is invoked. |
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800 | |
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801 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
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802 | ensure proper operations with regards to other event watchers. |
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803 | |
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804 | If you cannot do this for whatever reason, you can also force a watcher |
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805 | to be called on every event loop iteration by installing a C<EV::check> |
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806 | watcher: |
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807 | |
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808 | my $async_check = EV::check sub { }; |
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809 | |
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810 | This ensures that perl shortly gets into control for a short time, and |
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811 | also ensures slower overall operation. |
757 | |
812 | |
758 | =head1 THREADS |
813 | =head1 THREADS |
759 | |
814 | |
760 | Threads are not supported by this module in any way. Perl pseudo-threads |
815 | Threads are not supported by this module in any way. Perl pseudo-threads |
761 | is evil stuff and must die. As soon as Perl gains real threads I will work |
816 | is evil stuff and must die. As soon as Perl gains real threads I will work |
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783 | our $DIED = sub { |
838 | our $DIED = sub { |
784 | warn "EV: error in callback (ignoring): $@"; |
839 | warn "EV: error in callback (ignoring): $@"; |
785 | }; |
840 | }; |
786 | |
841 | |
787 | default_loop |
842 | default_loop |
788 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
843 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
789 | |
844 | |
790 | 1; |
845 | 1; |
791 | |
846 | |
792 | =head1 SEE ALSO |
847 | =head1 SEE ALSO |
793 | |
848 | |