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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 = '1.4'; |
73 | our $VERSION = '1.7'; |
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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… | |
131 | innermost call to EV::loop return. |
132 | innermost call to EV::loop return. |
132 | |
133 | |
133 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
134 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
134 | fast as possible. |
135 | fast as possible. |
135 | |
136 | |
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137 | =item $count = EV::loop_count |
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138 | |
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139 | Return the number of times the event loop has polled for new |
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140 | events. Sometiems useful as a generation counter. |
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141 | |
136 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
142 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
137 | |
143 | |
138 | This function rolls together an I/O and a timer watcher for a single |
144 | This function rolls together an I/O and a timer watcher for a single |
139 | one-shot event without the need for managing a watcher object. |
145 | one-shot event without the need for managing a watcher object. |
140 | |
146 | |
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175 | events. |
181 | events. |
176 | |
182 | |
177 | Each watcher type has its associated bit in revents, so you can use the |
183 | Each watcher type has its associated bit in revents, so you can use the |
178 | same callback for multiple watchers. The event mask is named after the |
184 | same callback for multiple watchers. The event mask is named after the |
179 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
185 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
180 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
186 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
181 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
187 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
182 | uses EV::TIMEOUT). |
188 | uses EV::TIMEOUT). |
183 | |
189 | |
184 | In the rare case where one wants to create a watcher but not start it at |
190 | In the rare case where one wants to create a watcher but not start it at |
185 | the same time, each constructor has a variant with a trailing C<_ns> in |
191 | the same time, each constructor has a variant with a trailing C<_ns> in |
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207 | |
213 | |
208 | =item $w->stop |
214 | =item $w->stop |
209 | |
215 | |
210 | Stop a watcher if it is active. Also clear any pending events (events that |
216 | Stop a watcher if it is active. Also clear any pending events (events that |
211 | have been received but that didn't yet result in a callback invocation), |
217 | have been received but that didn't yet result in a callback invocation), |
212 | regardless of wether the watcher was active or not. |
218 | regardless of whether the watcher was active or not. |
213 | |
219 | |
214 | =item $bool = $w->is_active |
220 | =item $bool = $w->is_active |
215 | |
221 | |
216 | Returns true if the watcher is active, false otherwise. |
222 | Returns true if the watcher is active, false otherwise. |
217 | |
223 | |
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272 | though your watcher is active, it won't keep C<EV::loop> from returning. |
278 | though your watcher is active, it won't keep C<EV::loop> from returning. |
273 | |
279 | |
274 | The initial value for keepalive is true (enabled), and you cna change it |
280 | The initial value for keepalive is true (enabled), and you cna change it |
275 | any time. |
281 | any time. |
276 | |
282 | |
277 | Example: Register an IO watcher for some UDP socket but do not keep the |
283 | Example: Register an I/O watcher for some UDP socket but do not keep the |
278 | event loop from running just because of that watcher. |
284 | event loop from running just because of that watcher. |
279 | |
285 | |
280 | my $udp_socket = ... |
286 | my $udp_socket = ... |
281 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
287 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
282 | $udp_watcher->keepalive (0); |
288 | $udp_watcher->keepalive (0); |
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286 | |
292 | |
287 | =head2 WATCHER TYPES |
293 | =head2 WATCHER TYPES |
288 | |
294 | |
289 | Each of the following subsections describes a single watcher type. |
295 | Each of the following subsections describes a single watcher type. |
290 | |
296 | |
291 | =head3 IO WATCHERS - is this file descriptor readable or writable? |
297 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
292 | |
298 | |
293 | =over 4 |
299 | =over 4 |
294 | |
300 | |
295 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
301 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
296 | |
302 | |
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576 | as even with OS-supported change notifications, this can be |
582 | as even with OS-supported change notifications, this can be |
577 | resource-intensive. |
583 | resource-intensive. |
578 | |
584 | |
579 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
585 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
580 | |
586 | |
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587 | =item ... = $w->stat |
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588 | |
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589 | This call is very similar to the perl C<stat> built-in: It stats (using |
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590 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
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591 | well as EV's idea of the current stat values) to the values found. |
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592 | |
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593 | In scalar context, a boolean is return indicating success or failure of |
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594 | the stat. In list context, the same 13-value list as with stat is returned |
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595 | (except that the blksize and blocks fields are not reliable). |
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596 | |
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597 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
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598 | actual error value) and the C<nlink> value is forced to zero (if the stat |
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599 | was successful then nlink is guaranteed to be non-zero). |
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600 | |
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601 | See also the next two entries for more info. |
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602 | |
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603 | =item ... = $w->attr |
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604 | |
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605 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
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606 | the values most recently detected by EV. See the next entry for more info. |
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607 | |
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608 | =item ... = $w->prev |
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609 | |
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610 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
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611 | the previous set of values, before the change. |
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612 | |
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613 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
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614 | to the values found I<before> a change was detected, while C<< $w->attr >> |
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615 | returns the values found leading to the change detection. The difference (if any) |
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616 | between C<prev> and C<attr> is what triggered the callback. |
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617 | |
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618 | If you did something to the filesystem object and do not want to trigger |
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619 | yet another change, you can call C<stat> to update EV's idea of what the |
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620 | current attributes are. |
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621 | |
581 | =item $w->set ($path, $interval) |
622 | =item $w->set ($path, $interval) |
582 | |
623 | |
583 | Reconfigures the watcher, see the constructor above for details. Can be |
624 | Reconfigures the watcher, see the constructor above for details. Can be |
584 | called at any time. |
625 | called at any time. |
585 | |
626 | |
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… | |
605 | |
646 | |
606 | =item $w = EV::idle $callback |
647 | =item $w = EV::idle $callback |
607 | |
648 | |
608 | =item $w = EV::idle_ns $callback |
649 | =item $w = EV::idle_ns $callback |
609 | |
650 | |
610 | Call the callback when there are no pending io, timer/periodic, signal or |
651 | Call the callback when there are no other pending watchers of the same or |
611 | child events, i.e. when the process is idle. |
652 | higher priority (excluding check, prepare and other idle watchers of the |
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653 | same or lower priority, of course). They are called idle watchers because |
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654 | when the watcher is the highest priority pending event in the process, the |
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655 | process is considered to be idle at that priority. |
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656 | |
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657 | If you want a watcher that is only ever called when I<no> other events are |
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658 | outstanding you have to set the priority to C<EV::MINPRI>. |
612 | |
659 | |
613 | The process will not block as long as any idle watchers are active, and |
660 | The process will not block as long as any idle watchers are active, and |
614 | they will be called repeatedly until stopped. |
661 | they will be called repeatedly until stopped. |
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662 | |
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663 | For example, if you have idle watchers at priority C<0> and C<1>, and |
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664 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
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665 | and the I/O watcher will always run when ready. Only when the idle watcher |
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666 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
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667 | pending with the C<0>-priority idle watcher be invoked. |
615 | |
668 | |
616 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
669 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
617 | |
670 | |
618 | =back |
671 | =back |
619 | |
672 | |
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660 | or return; |
713 | or return; |
661 | |
714 | |
662 | # make the dispatcher handle any outstanding stuff |
715 | # make the dispatcher handle any outstanding stuff |
663 | ... not shown |
716 | ... not shown |
664 | |
717 | |
665 | # create an IO watcher for each and every socket |
718 | # create an I/O watcher for each and every socket |
666 | @snmp_watcher = ( |
719 | @snmp_watcher = ( |
667 | (map { EV::io $_, EV::READ, sub { } } |
720 | (map { EV::io $_, EV::READ, sub { } } |
668 | keys %{ $dispatcher->{_descriptors} }), |
721 | keys %{ $dispatcher->{_descriptors} }), |
669 | |
722 | |
670 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
723 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
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712 | |
765 | |
713 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
766 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
714 | |
767 | |
715 | =back |
768 | =back |
716 | |
769 | |
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770 | |
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771 | =head1 PERL SIGNALS |
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772 | |
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773 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
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774 | with EV is as the same as any other C library: Perl-signals will only be |
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775 | handled when Perl runs, which means your signal handler might be invoked |
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776 | only the next time an event callback is invoked. |
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777 | |
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778 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
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779 | ensure proper operations with regards to other event watchers. |
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780 | |
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781 | If you cannot do this for whatever reason, you can also force a watcher |
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782 | to be called on every event loop iteration by installing a C<EV::check> |
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783 | watcher: |
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784 | |
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785 | my $async_check = EV::check sub { }; |
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786 | |
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787 | This ensures that perl shortly gets into control for a short time, and |
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788 | also ensures slower overall operation. |
717 | |
789 | |
718 | =head1 THREADS |
790 | =head1 THREADS |
719 | |
791 | |
720 | Threads are not supported by this module in any way. Perl pseudo-threads |
792 | Threads are not supported by this module in any way. Perl pseudo-threads |
721 | is evil stuff and must die. As soon as Perl gains real threads I will work |
793 | is evil stuff and must die. As soon as Perl gains real threads I will work |
… | |
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749 | |
821 | |
750 | 1; |
822 | 1; |
751 | |
823 | |
752 | =head1 SEE ALSO |
824 | =head1 SEE ALSO |
753 | |
825 | |
754 | L<EV::DNS>. |
826 | L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as |
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827 | event loop), L<Coro::EV> (efficient coroutines with EV). |
755 | |
828 | |
756 | =head1 AUTHOR |
829 | =head1 AUTHOR |
757 | |
830 | |
758 | Marc Lehmann <schmorp@schmorp.de> |
831 | Marc Lehmann <schmorp@schmorp.de> |
759 | http://home.schmorp.de/ |
832 | http://home.schmorp.de/ |