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Revision 1.94 by root, Tue May 20 23:54:05 2008 UTC vs.
Revision 1.118 by root, Tue Jul 14 20:31:21 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 = '3.4'; 84 our $VERSION = '3.7';
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
135this fucntion automatically, at some performance loss (refer to the libev 148this function automatically, at some performance loss (refer to the libev
136documentation). 149documentation).
137 150
151=item $loop->loop_verify
152
153Calls C<ev_verify> to make internal consistency checks (for debugging
154libev) and abort the program if any data structures were found to be
155corrupted.
156
138=item $loop = EV::default_loop [$flags] 157=item $loop = EV::default_loop [$flags]
139 158
140Return the default loop (which is a singleton object). 159Return the default loop (which is a singleton object). Since this module
160already creates the default loop with default flags, specifying flags here
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.
141 164
142=back 165=back
143 166
144 167
145=head1 BASIC INTERFACE 168=head1 BASIC INTERFACE
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175=item $time = EV::now 198=item $time = EV::now
176 199
177=item $time = $loop->now 200=item $time = $loop->now
178 201
179Returns the time the last event loop iteration has been started. This 202Returns the time the last event loop iteration has been started. This
180is 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
181usually faster then calling EV::time. 204usually faster then calling EV::time.
182 205
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
183=item $backend = EV::backend 248=item $backend = EV::backend
184 249
185=item $backend = $loop->backend 250=item $backend = $loop->backend
186 251
187Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
188or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
189 254
190=item EV::loop [$flags] 255=item EV::loop [$flags]
191 256
192=item $loop->loop ([$flags]) 257=item $loop->loop ([$flags])
193 258
… …
213=item $count = EV::loop_count 278=item $count = EV::loop_count
214 279
215=item $count = $loop->loop_count 280=item $count = $loop->loop_count
216 281
217Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
218events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
219 284
220=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
221 286
222=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
223 288
… …
263 328
264=item $loop->set_timeout_collect_interval ($time) 329=item $loop->set_timeout_collect_interval ($time)
265 330
266These 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
267wait interval for timer events. See the libev documentation at 332wait interval for timer events. See the libev documentation at
268L<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>
269a more detailed discussion. 334(locally installed as F<EV::libev>) for a more detailed discussion.
270 335
271=back 336=back
272 337
273 338
274=head1 WATCHER OBJECTS 339=head1 WATCHER OBJECTS
275 340
276A watcher is an object that gets created to record your interest in some 341A watcher is an object that gets created to record your interest in some
277event. For instance, if you want to wait for STDIN to become readable, you 342event. For instance, if you want to wait for STDIN to become readable, you
278would create an EV::io watcher for that: 343would create an EV::io watcher for that:
279 344
280 my $watcher = EV::io *STDIN, EV::READ, sub { 345 my $watcher = EV::io *STDIN, EV::READ, sub {
281 my ($watcher, $revents) = @_; 346 my ($watcher, $revents) = @_;
282 warn "yeah, STDIN should now be readable without blocking!\n" 347 warn "yeah, STDIN should now be readable without blocking!\n"
283 }; 348 };
284 349
285All watchers can be active (waiting for events) or inactive (paused). Only 350All watchers can be active (waiting for events) or inactive (paused). Only
286active watchers will have their callbacks invoked. All callbacks will be 351active watchers will have their callbacks invoked. All callbacks will be
287called with at least two arguments: the watcher and a bitmask of received 352called with at least two arguments: the watcher and a bitmask of received
288events. 353events.
289 354
290Each watcher type has its associated bit in revents, so you can use the 355Each watcher type has its associated bit in revents, so you can use the
291same callback for multiple watchers. The event mask is named after the 356same callback for multiple watchers. The event mask is named after the
292type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 357type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
293EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 358EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
294(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 359(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
295uses EV::TIMEOUT). 360uses EV::TIMEOUT).
296 361
297In the rare case where one wants to create a watcher but not start it at 362In the rare case where one wants to create a watcher but not start it at
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393because you happen to have this long-running UDP port watcher. 458because you happen to have this long-running UDP port watcher.
394 459
395In this case you can clear the keepalive status, which means that even 460In this case you can clear the keepalive status, which means that even
396though your watcher is active, it won't keep C<EV::loop> from returning. 461though your watcher is active, it won't keep C<EV::loop> from returning.
397 462
398The initial value for keepalive is true (enabled), and you cna change it 463The initial value for keepalive is true (enabled), and you can change it
399any time. 464any time.
400 465
401Example: Register an I/O watcher for some UDP socket but do not keep the 466Example: Register an I/O watcher for some UDP socket but do not keep the
402event loop from running just because of that watcher. 467event loop from running just because of that watcher.
403 468
404 my $udp_socket = ... 469 my $udp_socket = ...
405 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 470 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
406 $1000udp_watcher->keepalive (0); 471 $udp_watcher->keepalive (0);
407 472
408=item $loop = $w->loop 473=item $loop = $w->loop
409 474
410Return the loop that this watcher is attached to. 475Return the loop that this watcher is attached to.
411 476
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897 # make the dispatcher handle any new stuff 962 # make the dispatcher handle any new stuff
898 ... not shown 963 ... not shown
899 }; 964 };
900 965
901The callbacks of the created watchers will not be called as the watchers 966The callbacks of the created watchers will not be called as the watchers
902are destroyed before this cna happen (remember EV::check gets called 967are destroyed before this can happen (remember EV::check gets called
903first). 968first).
904 969
905The C<check_ns> variant doesn't start (activate) the newly created watcher. 970The C<check_ns> variant doesn't start (activate) the newly created watcher.
906 971
907=back 972=back
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938loop, other types of watchers might be handled in a delayed or incorrect 1003loop, other types of watchers might be handled in a delayed or incorrect
939fashion and must not be used). 1004fashion and must not be used).
940 1005
941See the libev documentation at 1006See the libev documentation at
942L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1007L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
943for more details. 1008(locally installed as F<EV::libev>) for more details.
944 1009
945In short, this watcher is most useful on BSD systems without working 1010In short, this watcher is most useful on BSD systems without working
946kqueue to still be able to handle a large number of sockets: 1011kqueue to still be able to handle a large number of sockets:
947 1012
948 my $socket_loop; 1013 my $socket_loop;
949 1014
950 # check wether we use SELECT or POLL _and_ KQUEUE is supported 1015 # check wether we use SELECT or POLL _and_ KQUEUE is supported
951 if ( 1016 if (
952 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 1017 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
953 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 1018 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
954 ) { 1019 ) {
955 # use kqueue for sockets 1020 # use kqueue for sockets
956 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 1021 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
957 } 1022 }
958 1023
959 # use the default loop otherwise 1024 # use the default loop otherwise
960 $socket_loop ||= EV::default_loop; 1025 $socket_loop ||= EV::default_loop;
961 1026
962=over 4 1027=over 4
963 1028
964=item $w = EV::embed $otherloop, $callback 1029=item $w = EV::embed $otherloop[, $callback]
965 1030
966=item $w = EV::embed_ns $otherloop, $callback 1031=item $w = EV::embed_ns $otherloop[, $callback]
967 1032
968=item $w = $loop->embed ($otherloop, $callback) 1033=item $w = $loop->embed ($otherloop[, $callback])
969 1034
970=item $w = $loop->embed_ns ($otherloop, $callback) 1035=item $w = $loop->embed_ns ($otherloop[, $callback])
971 1036
972Call the callback when the embedded event loop (C<$otherloop>) has any 1037Call the callback when the embedded event loop (C<$otherloop>) has any
973I/O activity. The C<$callback> should alwas be specified as C<undef> in 1038I/O activity. The C<$callback> is optional: if it is missing, then the
974this version of EV, which means the embedded event loop will be managed 1039embedded event loop will be managed automatically (which is recommended),
975automatically. 1040otherwise you have to invoke C<sweep> yourself.
976 1041
977The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1042The C<embed_ns> variant doesn't start (activate) the newly created watcher.
978 1043
979=back 1044=back
980 1045
981=head3 ASYNC WATCHERS - how to wake up another event loop 1046=head3 ASYNC WATCHERS - how to wake up another event loop
982 1047
983Async watchers are provided by EV, but have little use in perl directly, as perl 1048Async watchers are provided by EV, but have little use in perl directly,
984neither supports threads nor direct access to signal handlers or other 1049as perl neither supports threads running in parallel nor direct access to
985contexts where they could be of value. 1050signal handlers or other contexts where they could be of value.
986 1051
987It is, however, possible to use them from the XS level. 1052It is, however, possible to use them from the XS level.
988 1053
989Please see the libev documentation for further details. 1054Please see the libev documentation for further details.
990 1055
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1018 my $async_check = EV::check sub { }; 1083 my $async_check = EV::check sub { };
1019 1084
1020This ensures that perl gets into control for a short time to handle any 1085This ensures that perl gets into control for a short time to handle any
1021pending signals, and also ensures (slightly) slower overall operation. 1086pending signals, and also ensures (slightly) slower overall operation.
1022 1087
1023=head1 THREADS 1088=head1 ITHREADS
1024 1089
1025Threads are not supported by this module in any way. Perl pseudo-threads 1090Ithreads are not supported by this module in any way. Perl pseudo-threads
1026is evil stuff and must die. As soon as Perl gains real threads I will work 1091is evil stuff and must die. Real threads as provided by Coro are fully
1027on thread support for it. 1092supported (and enhanced support is available via L<Coro::EV>).
1028 1093
1029=head1 FORK 1094=head1 FORK
1030 1095
1031Most of the "improved" event delivering mechanisms of modern operating 1096Most of the "improved" event delivering mechanisms of modern operating
1032systems have quite a few problems with fork(2) (to put it bluntly: it is 1097systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1061coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for 1126coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1062event-loop agnostic and portable event driven programming. 1127event-loop agnostic and portable event driven programming.
1063 1128
1064=head1 AUTHOR 1129=head1 AUTHOR
1065 1130
1066 Marc Lehmann <schmorp@schmorp.de> 1131 Marc Lehmann <schmorp@schmorp.de>
1067 http://home.schmorp.de/ 1132 http://home.schmorp.de/
1068 1133
1069=cut 1134=cut
1070 1135

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