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Revision 1.97 by root, Mon May 26 05:37:18 2008 UTC vs.
Revision 1.124 by root, Tue Dec 1 13:56:33 2009 UTC

… …
2 2
3EV - perl interface to libev, a high performance full-featured event loop 3EV - perl interface to libev, a high performance full-featured event loop
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use EV; 7 use EV;
8
9 # TIMERS
10
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
8 39
9 # TIMERS 40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
10 44
11 my $w = EV::timer 2, 0, sub {
12 warn "is called after 2s";
13 };
14
15 my $w = EV::timer 2, 2, sub {
16 warn "is called roughly every 2s (repeat = 2)";
17 };
18
19 undef $w; # destroy event watcher again
20
21 my $w = EV::periodic 0, 60, 0, sub {
22 warn "is called every minute, on the minute, exactly";
23 };
24
25 # IO
26
27 my $w = EV::io *STDIN, EV::READ, sub {
28 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29 warn "stdin is readable, you entered: ", <STDIN>;
30 };
31
32 # SIGNALS
33
34 my $w = EV::signal 'QUIT', sub {
35 warn "sigquit received\n";
36 };
37
38 # CHILD/PID STATUS CHANGES
39
40 my $w = EV::child 666, 0, sub {
41 my ($w, $revents) = @_;
42 my $status = $w->rstatus;
43 };
44
45 # STAT CHANGES 45 # STAT CHANGES
46 my $w = EV::stat "/etc/passwd", 10, sub { 46 my $w = EV::stat "/etc/passwd", 10, sub {
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::loop; # loop until EV::unloop is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
55 55
56=head1 DESCRIPTION 56=head1 DESCRIPTION
57 57
58This module provides an interface to libev 58This 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
60below is comprehensive, one might also consult the documentation of libev 60below is comprehensive, one might also consult the documentation of
61itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more 61libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62subtle details on watcher semantics or some discussion on the available 62F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just 63discussion on the available backends, or how to force a specific backend
64about in any case because it has much more detailed information. 64with C<LIBEV_FLAGS>, or just about in any case because it has much more
65detailed information.
65 66
66This module is very fast and scalable. It is actually so fast that you 67This module is very fast and scalable. It is actually so fast that you
67can use it through the L<AnyEvent> module, stay portable to other event 68can use it through the L<AnyEvent> module, stay portable to other event
68loops (if you don't rely on any watcher types not available through it) 69loops (if you don't rely on any watcher types not available through it)
69and still be faster than with any other event loop currently supported in 70and still be faster than with any other event loop currently supported in
70Perl. 71Perl.
71 72
73=head2 MODULE EXPORTS
74
75This module does not export any symbols.
76
72=cut 77=cut
73 78
74package EV; 79package EV;
75 80
76use strict; 81use common::sense;
77 82
78BEGIN { 83BEGIN {
79 our $VERSION = '3.42'; 84 our $VERSION = '3.8';
80 use XSLoader; 85 use XSLoader;
81 XSLoader::load "EV", $VERSION; 86 XSLoader::load "EV", $VERSION;
82} 87}
83 88
84@EV::IO::ISA = 89@EV::IO::ISA =
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111default loop as this is fastest (perl-wise), best supported by other 116default loop as this is fastest (perl-wise), best supported by other
112modules (e.g. AnyEvent or Coro) and most portable event loop. 117modules (e.g. AnyEvent or Coro) and most portable event loop.
113 118
114For specific programs you can create additional event loops dynamically. 119For specific programs you can create additional event loops dynamically.
115 120
116=over 4 121If you want to take advantage of kqueue (which often works properly for
122sockets only) even though the default loop doesn't enable it, you can
123I<embed> a kqueue loop into the default loop: running the default loop
124will then also service the kqueue loop to some extent. See the example in
125the section about embed watchers for an example on how to achieve that.
117 126
127=over 4
128
118=item $loop = new EV::loop [$flags] 129=item $loop = new EV::Loop [$flags]
119 130
120Create a new event loop as per the specified flags. Please refer to the 131Create a new event loop as per the specified flags. Please refer to
121C<ev_loop_new ()> function description in the libev documentation 132the C<ev_loop_new ()> function description in the libev documentation
122(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) 133(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
123for more info. 134or locally-installed as F<EV::libev> manpage) for more info.
124 135
125The loop will automatically be destroyed when it is no longer referenced 136The loop will automatically be destroyed when it is no longer referenced
126by any watcher and the loop object goes out of scope. 137by any watcher and the loop object goes out of scope.
127 138
128Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 139If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
129is protected by this module. 140is recommended, as only the default event loop is protected by this
141module. If you I<are> embedding this loop in the default loop, this is not
142necessary, as C<EV::embed> automatically does the right thing on fork.
130 143
131=item $loop->loop_fork 144=item $loop->loop_fork
132 145
133Must be called after a fork in the child, before entering or continuing 146Must be called after a fork in the child, before entering or continuing
134the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls 147the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
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136documentation). 149documentation).
137 150
138=item $loop->loop_verify 151=item $loop->loop_verify
139 152
140Calls C<ev_verify> to make internal consistency checks (for debugging 153Calls C<ev_verify> to make internal consistency checks (for debugging
141libev) and abort the program if any data structures wree found to be 154libev) and abort the program if any data structures were found to be
142corrupted. 155corrupted.
143 156
144=item $loop = EV::default_loop [$flags] 157=item $loop = EV::default_loop [$flags]
145 158
146Return the default loop (which is a singleton object). Since this module 159Return the default loop (which is a singleton object). Since this module
147already creates the default loop with default flags, specifying flags here 160already creates the default loop with default flags, specifying flags here
148will not have any effect unless you destroy the default loop. 161will not have any effect unless you destroy the default loop first, which
162isn't supported. So in short: don't do it, and if you break it, you get to
163keep the pieces.
149 164
150=back 165=back
151 166
152 167
153=head1 BASIC INTERFACE 168=head1 BASIC INTERFACE
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183=item $time = EV::now 198=item $time = EV::now
184 199
185=item $time = $loop->now 200=item $time = $loop->now
186 201
187Returns the time the last event loop iteration has been started. This 202Returns the time the last event loop iteration has been started. This
188is the time that (relative) timers are based on, and refering to it is 203is the time that (relative) timers are based on, and referring to it is
189usually faster then calling EV::time. 204usually faster then calling EV::time.
190 205
206=item EV::now_update
207
208=item $loop->now_update
209
210Establishes the current time by querying the kernel, updating the time
211returned by C<EV::now> in the progress. This is a costly operation and
212is usually done automatically within C<EV::loop>.
213
214This function is rarely useful, but when some event callback runs for a
215very long time without entering the event loop, updating libev's idea of
216the current time is a good idea.
217
218=item EV::suspend
219
220=item $loop->suspend
221
222=item EV::resume
223
224=item $loop->resume
225
226These two functions suspend and resume a loop, for use when the loop is
227not used for a while and timeouts should not be processed.
228
229A typical use case would be an interactive program such as a game: When
230the user presses C<^Z> to suspend the game and resumes it an hour later it
231would be best to handle timeouts as if no time had actually passed while
232the program was suspended. This can be achieved by calling C<suspend>
233in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
234C<resume> directly afterwards to resume timer processing.
235
236Effectively, all C<timer> watchers will be delayed by the time spend
237between C<suspend> and C<resume>, and all C<periodic> watchers
238will be rescheduled (that is, they will lose any events that would have
239occured while suspended).
240
241After calling C<suspend> you B<must not> call I<any> function on the given
242loop other than C<resume>, and you B<must not> call C<resume>
243without a previous call to C<suspend>.
244
245Calling C<suspend>/C<resume> has the side effect of updating the event
246loop time (see C<now_update>).
247
191=item $backend = EV::backend 248=item $backend = EV::backend
192 249
193=item $backend = $loop->backend 250=item $backend = $loop->backend
194 251
195Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
196or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
197 254
198=item EV::loop [$flags] 255=item EV::loop [$flags]
199 256
200=item $loop->loop ([$flags]) 257=item $loop->loop ([$flags])
201 258
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221=item $count = EV::loop_count 278=item $count = EV::loop_count
222 279
223=item $count = $loop->loop_count 280=item $count = $loop->loop_count
224 281
225Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
226events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
227 284
228=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
229 286
230=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
231 288
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271 328
272=item $loop->set_timeout_collect_interval ($time) 329=item $loop->set_timeout_collect_interval ($time)
273 330
274These advanced functions set the minimum block interval when polling for I/O events and the minimum 331These advanced functions set the minimum block interval when polling for I/O events and the minimum
275wait interval for timer events. See the libev documentation at 332wait interval for timer events. See the libev documentation at
276L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for 333L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
277a more detailed discussion. 334(locally installed as F<EV::libev>) for a more detailed discussion.
335
336=item $count = EV::pending_count
337
338=item $count = $loop->pending_count
339
340Returns the number of currently pending watchers.
341
342=item EV::invoke_pending
343
344=item $loop->invoke_pending
345
346Invoke all currently pending watchers.
278 347
279=back 348=back
280 349
281 350
282=head1 WATCHER OBJECTS 351=head1 WATCHER OBJECTS
283 352
284A watcher is an object that gets created to record your interest in some 353A watcher is an object that gets created to record your interest in some
285event. For instance, if you want to wait for STDIN to become readable, you 354event. For instance, if you want to wait for STDIN to become readable, you
286would create an EV::io watcher for that: 355would create an EV::io watcher for that:
287 356
288 my $watcher = EV::io *STDIN, EV::READ, sub { 357 my $watcher = EV::io *STDIN, EV::READ, sub {
289 my ($watcher, $revents) = @_; 358 my ($watcher, $revents) = @_;
290 warn "yeah, STDIN should now be readable without blocking!\n" 359 warn "yeah, STDIN should now be readable without blocking!\n"
291 }; 360 };
292 361
293All watchers can be active (waiting for events) or inactive (paused). Only 362All watchers can be active (waiting for events) or inactive (paused). Only
294active watchers will have their callbacks invoked. All callbacks will be 363active watchers will have their callbacks invoked. All callbacks will be
295called with at least two arguments: the watcher and a bitmask of received 364called with at least two arguments: the watcher and a bitmask of received
296events. 365events.
297 366
298Each watcher type has its associated bit in revents, so you can use the 367Each watcher type has its associated bit in revents, so you can use the
299same callback for multiple watchers. The event mask is named after the 368same callback for multiple watchers. The event mask is named after the
300type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 369type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
301EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 370EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
302(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 371(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
303uses EV::TIMEOUT). 372uses EV::TIMEOUT).
304 373
305In the rare case where one wants to create a watcher but not start it at 374In the rare case where one wants to create a watcher but not start it at
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387 456
388=item $previous_state = $w->keepalive ($bool) 457=item $previous_state = $w->keepalive ($bool)
389 458
390Normally, C<EV::loop> will return when there are no active watchers 459Normally, C<EV::loop> will return when there are no active watchers
391(which is a "deadlock" because no progress can be made anymore). This is 460(which is a "deadlock" because no progress can be made anymore). This is
392convinient because it allows you to start your watchers (and your jobs), 461convenient because it allows you to start your watchers (and your jobs),
393call C<EV::loop> once and when it returns you know that all your jobs are 462call C<EV::loop> once and when it returns you know that all your jobs are
394finished (or they forgot to register some watchers for their task :). 463finished (or they forgot to register some watchers for their task :).
395 464
396Sometimes, however, this gets in your way, for example when the module 465Sometimes, however, this gets in your way, for example when the module
397that calls C<EV::loop> (usually the main program) is not the same module 466that calls C<EV::loop> (usually the main program) is not the same module
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401because you happen to have this long-running UDP port watcher. 470because you happen to have this long-running UDP port watcher.
402 471
403In this case you can clear the keepalive status, which means that even 472In this case you can clear the keepalive status, which means that even
404though your watcher is active, it won't keep C<EV::loop> from returning. 473though your watcher is active, it won't keep C<EV::loop> from returning.
405 474
406The initial value for keepalive is true (enabled), and you cna change it 475The initial value for keepalive is true (enabled), and you can change it
407any time. 476any time.
408 477
409Example: Register an I/O watcher for some UDP socket but do not keep the 478Example: Register an I/O watcher for some UDP socket but do not keep the
410event loop from running just because of that watcher. 479event loop from running just because of that watcher.
411 480
412 my $udp_socket = ... 481 my $udp_socket = ...
413 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 482 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
414 $1000udp_watcher->keepalive (0); 483 $udp_watcher->keepalive (0);
415 484
416=item $loop = $w->loop 485=item $loop = $w->loop
417 486
418Return the loop that this watcher is attached to. 487Return the loop that this watcher is attached to.
419 488
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629 698
630=item $w = EV::signal $signal, $callback 699=item $w = EV::signal $signal, $callback
631 700
632=item $w = EV::signal_ns $signal, $callback 701=item $w = EV::signal_ns $signal, $callback
633 702
703=item $w = $loop->signal ($signal, $callback)
704
705=item $w = $loop->signal_ns ($signal, $callback)
706
634Call the callback when $signal is received (the signal can be specified by 707Call the callback when $signal is received (the signal can be specified by
635number or by name, just as with C<kill> or C<%SIG>). 708number or by name, just as with C<kill> or C<%SIG>).
709
710Only one event loop can grab a given signal - attempting to grab the same
711signal from two EV loops will crash the program immediately or cause data
712corruption.
636 713
637EV will grab the signal for the process (the kernel only allows one 714EV will grab the signal for the process (the kernel only allows one
638component to receive a signal at a time) when you start a signal watcher, 715component to receive a signal at a time) when you start a signal watcher,
639and removes it again when you stop it. Perl does the same when you 716and removes it again when you stop it. Perl does the same when you
640add/remove callbacks to C<%SIG>, so watch out. 717add/remove callbacks to C<%SIG>, so watch out.
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905 # make the dispatcher handle any new stuff 982 # make the dispatcher handle any new stuff
906 ... not shown 983 ... not shown
907 }; 984 };
908 985
909The callbacks of the created watchers will not be called as the watchers 986The callbacks of the created watchers will not be called as the watchers
910are destroyed before this cna happen (remember EV::check gets called 987are destroyed before this can happen (remember EV::check gets called
911first). 988first).
912 989
913The C<check_ns> variant doesn't start (activate) the newly created watcher. 990The C<check_ns> variant doesn't start (activate) the newly created watcher.
914 991
915=back 992=back
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946loop, other types of watchers might be handled in a delayed or incorrect 1023loop, other types of watchers might be handled in a delayed or incorrect
947fashion and must not be used). 1024fashion and must not be used).
948 1025
949See the libev documentation at 1026See the libev documentation at
950L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1027L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
951for more details. 1028(locally installed as F<EV::libev>) for more details.
952 1029
953In short, this watcher is most useful on BSD systems without working 1030In short, this watcher is most useful on BSD systems without working
954kqueue to still be able to handle a large number of sockets: 1031kqueue to still be able to handle a large number of sockets:
955 1032
956 my $socket_loop; 1033 my $socket_loop;
957 1034
958 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1035 # check wether we use SELECT or POLL _and_ KQUEUE is supported
959 if ( 1036 if (
960 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1037 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
961 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1038 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
962 ) { 1039 ) {
963 # use kqueue for sockets 1040 # use kqueue for sockets
964 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1041 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
965 } 1042 }
966 1043
967 # use the default loop otherwise 1044 # use the default loop otherwise
968 $socket_loop ||= EV::default_loop; 1045 $socket_loop ||= EV::default_loop;
969 1046
970=over 4 1047=over 4
971 1048
972=item $w = EV::embed $otherloop, $callback 1049=item $w = EV::embed $otherloop[, $callback]
973 1050
974=item $w = EV::embed_ns $otherloop, $callback 1051=item $w = EV::embed_ns $otherloop[, $callback]
975 1052
976=item $w = $loop->embed ($otherloop, $callback) 1053=item $w = $loop->embed ($otherloop[, $callback])
977 1054
978=item $w = $loop->embed_ns ($otherloop, $callback) 1055=item $w = $loop->embed_ns ($otherloop[, $callback])
979 1056
980Call the callback when the embedded event loop (C<$otherloop>) has any 1057Call the callback when the embedded event loop (C<$otherloop>) has any
981I/O activity. The C<$callback> should alwas be specified as C<undef> in 1058I/O activity. The C<$callback> is optional: if it is missing, then the
982this version of EV, which means the embedded event loop will be managed 1059embedded event loop will be managed automatically (which is recommended),
983automatically. 1060otherwise you have to invoke C<sweep> yourself.
984 1061
985The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1062The C<embed_ns> variant doesn't start (activate) the newly created watcher.
986 1063
987=back 1064=back
988 1065
989=head3 ASYNC WATCHERS - how to wake up another event loop 1066=head3 ASYNC WATCHERS - how to wake up another event loop
990 1067
991Async watchers are provided by EV, but have little use in perl directly, as perl 1068Async watchers are provided by EV, but have little use in perl directly,
992neither supports threads nor direct access to signal handlers or other 1069as perl neither supports threads running in parallel nor direct access to
993contexts where they could be of value. 1070signal handlers or other contexts where they could be of value.
994 1071
995It is, however, possible to use them from the XS level. 1072It is, however, possible to use them from the XS level.
996 1073
997Please see the libev documentation for further details. 1074Please see the libev documentation for further details.
998 1075
… …
1026 my $async_check = EV::check sub { }; 1103 my $async_check = EV::check sub { };
1027 1104
1028This ensures that perl gets into control for a short time to handle any 1105This ensures that perl gets into control for a short time to handle any
1029pending signals, and also ensures (slightly) slower overall operation. 1106pending signals, and also ensures (slightly) slower overall operation.
1030 1107
1031=head1 THREADS 1108=head1 ITHREADS
1032 1109
1033Threads are not supported by this module in any way. Perl pseudo-threads 1110Ithreads are not supported by this module in any way. Perl pseudo-threads
1034is evil stuff and must die. As soon as Perl gains real threads I will work 1111is evil stuff and must die. Real threads as provided by Coro are fully
1035on thread support for it. 1112supported (and enhanced support is available via L<Coro::EV>).
1036 1113
1037=head1 FORK 1114=head1 FORK
1038 1115
1039Most of the "improved" event delivering mechanisms of modern operating 1116Most of the "improved" event delivering mechanisms of modern operating
1040systems have quite a few problems with fork(2) (to put it bluntly: it is 1117systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1069coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for 1146coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1070event-loop agnostic and portable event driven programming. 1147event-loop agnostic and portable event driven programming.
1071 1148
1072=head1 AUTHOR 1149=head1 AUTHOR
1073 1150
1074 Marc Lehmann <schmorp@schmorp.de> 1151 Marc Lehmann <schmorp@schmorp.de>
1075 http://home.schmorp.de/ 1152 http://home.schmorp.de/
1076 1153
1077=cut 1154=cut
1078 1155

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