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Revision 1.32 by root, Tue Apr 28 00:50:57 2009 UTC vs.
Revision 1.38 by root, Mon Oct 25 11:30:45 2010 UTC

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2 EV - perl interface to libev, a high performance full-featured event 2 EV - perl interface to libev, a high performance full-featured event
3 loop 3 loop
4 4
5SYNOPSIS 5SYNOPSIS
6 use EV; 6 use EV;
7 7
8 # TIMERS 8 # TIMERS
9 9
10 my $w = EV::timer 2, 0, sub { 10 my $w = EV::timer 2, 0, sub {
11 warn "is called after 2s"; 11 warn "is called after 2s";
12 }; 12 };
13 13
14 my $w = EV::timer 2, 2, sub { 14 my $w = EV::timer 2, 2, sub {
15 warn "is called roughly every 2s (repeat = 2)"; 15 warn "is called roughly every 2s (repeat = 2)";
16 }; 16 };
17 17
18 undef $w; # destroy event watcher again 18 undef $w; # destroy event watcher again
19 19
20 my $w = EV::periodic 0, 60, 0, sub { 20 my $w = EV::periodic 0, 60, 0, sub {
21 warn "is called every minute, on the minute, exactly"; 21 warn "is called every minute, on the minute, exactly";
22 }; 22 };
23
23 24 # IO
24 # IO 25
25
26 my $w = EV::io *STDIN, EV::READ, sub { 26 my $w = EV::io *STDIN, EV::READ, sub {
27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask 27 my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28 warn "stdin is readable, you entered: ", <STDIN>; 28 warn "stdin is readable, you entered: ", <STDIN>;
29 }; 29 };
30 30
31 # SIGNALS 31 # SIGNALS
32 32
33 my $w = EV::signal 'QUIT', sub { 33 my $w = EV::signal 'QUIT', sub {
34 warn "sigquit received\n"; 34 warn "sigquit received\n";
35 }; 35 };
36 36
37 # CHILD/PID STATUS CHANGES 37 # CHILD/PID STATUS CHANGES
38 38
39 my $w = EV::child 666, 0, sub { 39 my $w = EV::child 666, 0, sub {
40 my ($w, $revents) = @_; 40 my ($w, $revents) = @_;
41 my $status = $w->rstatus; 41 my $status = $w->rstatus;
42 }; 42 };
43 43
44 # STAT CHANGES 44 # STAT CHANGES
45 my $w = EV::stat "/etc/passwd", 10, sub { 45 my $w = EV::stat "/etc/passwd", 10, sub {
46 my ($w, $revents) = @_; 46 my ($w, $revents) = @_;
47 warn $w->path, " has changed somehow.\n"; 47 warn $w->path, " has changed somehow.\n";
48 }; 48 };
49 49
50 # MAINLOOP 50 # MAINLOOP
51 EV::loop; # loop until EV::unloop is called or all watchers stop 51 EV::loop; # loop until EV::unloop is called or all watchers stop
52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 52 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
53 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 53 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
54
55BEFORE YOU START USING THIS MODULE
56 If you only need timer, I/O, signal, child and idle watchers and not the
57 advanced functionality of this module, consider using AnyEvent instead,
58 specifically the simplified API described in AE.
59
60 When used with EV as backend, the AE API is as fast as the native EV
61 API, but your programs/modules will still run with many other event
62 loops.
54 63
55DESCRIPTION 64DESCRIPTION
56 This module provides an interface to libev 65 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 66 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 67 below is comprehensive, one might also consult the documentation of
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66 can use it through the AnyEvent module, stay portable to other event 75 can use it through the AnyEvent module, stay portable to other event
67 loops (if you don't rely on any watcher types not available through it) 76 loops (if you don't rely on any watcher types not available through it)
68 and still be faster than with any other event loop currently supported 77 and still be faster than with any other event loop currently supported
69 in Perl. 78 in Perl.
70 79
80 PORTING FROM EV 3.X to 4.X
81 EV version 4 introduces a number of incompatible changes summarised
82 here. According to the depreciation strategy used by libev, there is a
83 compatibility layer in place so programs should continue to run
84 unchanged (the XS interface lacks this layer, so programs using that one
85 need to be updated).
86
87 This compatibility layer will be switched off in some future release.
88
89 All changes relevant to Perl are renames of symbols, functions and
90 methods:
91
92 EV::loop => EV::run
93 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
94 EV::LOOP_ONESHOT => EV::RUN_ONCE
95
96 EV::unloop => EV::break
97 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
98 EV::UNLOOP_ONE => EV::BREAK_ONE
99 EV::UNLOOP_ALL => EV::BREAK_ALL
100
101 EV::TIMEOUT => EV::TIMER
102
103 EV::loop_count => EV::iteration
104 EV::loop_depth => EV::depth
105 EV::loop_verify => EV::verify
106
107 The loop object methods corresponding to the functions above have been
108 similarly renamed.
109
71 MODULE EXPORTS 110 MODULE EXPORTS
72 This module does not export any symbols. 111 This module does not export any symbols.
73 112
74EVENT LOOPS 113EVENT LOOPS
75 EV supports multiple event loops: There is a single "default event loop" 114 EV supports multiple event loops: There is a single "default event loop"
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235 Otherwise a EV::timer with this value will be started. 274 Otherwise a EV::timer with this value will be started.
236 275
237 When an error occurs or either the timeout or I/O watcher triggers, 276 When an error occurs or either the timeout or I/O watcher triggers,
238 then the callback will be called with the received event set (in 277 then the callback will be called with the received event set (in
239 general you can expect it to be a combination of "EV::ERROR", 278 general you can expect it to be a combination of "EV::ERROR",
240 "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). 279 "EV::READ", "EV::WRITE" and "EV::TIMER").
241 280
242 EV::once doesn't return anything: the watchers stay active till 281 EV::once doesn't return anything: the watchers stay active till
243 either of them triggers, then they will be stopped and freed, and 282 either of them triggers, then they will be stopped and freed, and
244 the callback invoked. 283 the callback invoked.
245 284
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263 the libev documentation at 302 the libev documentation at
264 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 303 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
265 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more 304 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
266 detailed discussion. 305 detailed discussion.
267 306
307 $count = EV::pending_count
308 $count = $loop->pending_count
309 Returns the number of currently pending watchers.
310
311 EV::invoke_pending
312 $loop->invoke_pending
313 Invoke all currently pending watchers.
314
268WATCHER OBJECTS 315WATCHER OBJECTS
269 A watcher is an object that gets created to record your interest in some 316 A watcher is an object that gets created to record your interest in some
270 event. For instance, if you want to wait for STDIN to become readable, 317 event. For instance, if you want to wait for STDIN to become readable,
271 you would create an EV::io watcher for that: 318 you would create an EV::io watcher for that:
272 319
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282 329
283 Each watcher type has its associated bit in revents, so you can use the 330 Each watcher type has its associated bit in revents, so you can use the
284 same callback for multiple watchers. The event mask is named after the 331 same callback for multiple watchers. The event mask is named after the
285 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 332 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
286 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 333 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
287 events (which can set both EV::READ and EV::WRITE bits), and EV::timer 334 events (which can set both EV::READ and EV::WRITE bits).
288 (which uses EV::TIMEOUT).
289 335
290 In the rare case where one wants to create a watcher but not start it at 336 In the rare case where one wants to create a watcher but not start it at
291 the same time, each constructor has a variant with a trailing "_ns" in 337 the same time, each constructor has a variant with a trailing "_ns" in
292 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 338 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
293 339
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358 the watcher isn't pending it does nothing and returns 0. 404 the watcher isn't pending it does nothing and returns 0.
359 405
360 $previous_state = $w->keepalive ($bool) 406 $previous_state = $w->keepalive ($bool)
361 Normally, "EV::loop" will return when there are no active watchers 407 Normally, "EV::loop" will return when there are no active watchers
362 (which is a "deadlock" because no progress can be made anymore). 408 (which is a "deadlock" because no progress can be made anymore).
363 This is convinient because it allows you to start your watchers (and 409 This is convenient because it allows you to start your watchers (and
364 your jobs), call "EV::loop" once and when it returns you know that 410 your jobs), call "EV::loop" once and when it returns you know that
365 all your jobs are finished (or they forgot to register some watchers 411 all your jobs are finished (or they forgot to register some watchers
366 for their task :). 412 for their task :).
367 413
368 Sometimes, however, this gets in your way, for example when the 414 Sometimes, however, this gets in your way, for example when the
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559 Return the time that the watcher is expected to trigger next. 605 Return the time that the watcher is expected to trigger next.
560 606
561 SIGNAL WATCHERS - signal me when a signal gets signalled! 607 SIGNAL WATCHERS - signal me when a signal gets signalled!
562 $w = EV::signal $signal, $callback 608 $w = EV::signal $signal, $callback
563 $w = EV::signal_ns $signal, $callback 609 $w = EV::signal_ns $signal, $callback
610 $w = $loop->signal ($signal, $callback)
611 $w = $loop->signal_ns ($signal, $callback)
564 Call the callback when $signal is received (the signal can be 612 Call the callback when $signal is received (the signal can be
565 specified by number or by name, just as with "kill" or %SIG). 613 specified by number or by name, just as with "kill" or %SIG).
614
615 Only one event loop can grab a given signal - attempting to grab the
616 same signal from two EV loops will crash the program immediately or
617 cause data corruption.
566 618
567 EV will grab the signal for the process (the kernel only allows one 619 EV will grab the signal for the process (the kernel only allows one
568 component to receive a signal at a time) when you start a signal 620 component to receive a signal at a time) when you start a signal
569 watcher, and removes it again when you stop it. Perl does the same 621 watcher, and removes it again when you stop it. Perl does the same
570 when you add/remove callbacks to %SIG, so watch out. 622 when you add/remove callbacks to %SIG, so watch out.
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744 $w = $loop->check_ns ($callback) 796 $w = $loop->check_ns ($callback)
745 Call the callback just after the process wakes up again (after it 797 Call the callback just after the process wakes up again (after it
746 has gathered events), but before any other callbacks have been 798 has gathered events), but before any other callbacks have been
747 invoked. 799 invoked.
748 800
749 This is used to integrate other event-based software into the EV 801 This can be used to integrate other event-based software into the EV
750 mainloop: You register a prepare callback and in there, you create 802 mainloop: You register a prepare callback and in there, you create
751 io and timer watchers as required by the other software. Here is a 803 io and timer watchers as required by the other software. Here is a
752 real-world example of integrating Net::SNMP (with some details left 804 real-world example of integrating Net::SNMP (with some details left
753 out): 805 out):
754 806
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790 watchers are destroyed before this can happen (remember EV::check 842 watchers are destroyed before this can happen (remember EV::check
791 gets called first). 843 gets called first).
792 844
793 The "check_ns" variant doesn't start (activate) the newly created 845 The "check_ns" variant doesn't start (activate) the newly created
794 watcher. 846 watcher.
847
848 EV::CHECK constant issues
849 Like all other watcher types, there is a bitmask constant for use in
850 $revents and other places. The "EV::CHECK" is special as it has the
851 same name as the "CHECK" sub called by Perl. This doesn't cause big
852 issues on newer perls (beginning with 5.8.9), but it means thatthe
853 constant must be *inlined*, i.e. runtime calls will not work. That
854 means that as long as you always "use EV" and then "EV::CHECK" you
855 are on the safe side.
795 856
796 FORK WATCHERS - the audacity to resume the event loop after a fork 857 FORK WATCHERS - the audacity to resume the event loop after a fork
797 Fork watchers are called when a "fork ()" was detected. The invocation 858 Fork watchers are called when a "fork ()" was detected. The invocation
798 is done before the event loop blocks next and before "check" watchers 859 is done before the event loop blocks next and before "check" watchers
799 are being called, and only in the child after the fork. 860 are being called, and only in the child after the fork.
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820 881
821 In short, this watcher is most useful on BSD systems without working 882 In short, this watcher is most useful on BSD systems without working
822 kqueue to still be able to handle a large number of sockets: 883 kqueue to still be able to handle a large number of sockets:
823 884
824 my $socket_loop; 885 my $socket_loop;
825 886
826 # check wether we use SELECT or POLL _and_ KQUEUE is supported 887 # check wether we use SELECT or POLL _and_ KQUEUE is supported
827 if ( 888 if (
828 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 889 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
829 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 890 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
830 ) { 891 ) {
831 # use kqueue for sockets 892 # use kqueue for sockets
832 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 893 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
833 } 894 }
834 895
835 # use the default loop otherwise 896 # use the default loop otherwise
836 $socket_loop ||= EV::default_loop; 897 $socket_loop ||= EV::default_loop;
837 898
838 $w = EV::embed $otherloop[, $callback] 899 $w = EV::embed $otherloop[, $callback]
839 $w = EV::embed_ns $otherloop[, $callback] 900 $w = EV::embed_ns $otherloop[, $callback]
840 $w = $loop->embed ($otherloop[, $callback]) 901 $w = $loop->embed ($otherloop[, $callback])
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847 The "embed_ns" variant doesn't start (activate) the newly created 908 The "embed_ns" variant doesn't start (activate) the newly created
848 watcher. 909 watcher.
849 910
850 ASYNC WATCHERS - how to wake up another event loop 911 ASYNC WATCHERS - how to wake up another event loop
851 Async watchers are provided by EV, but have little use in perl directly, 912 Async watchers are provided by EV, but have little use in perl directly,
852 as perl neither supports threads nor direct access to signal handlers or 913 as perl neither supports threads running in parallel nor direct access
853 other contexts where they could be of value. 914 to signal handlers or other contexts where they could be of value.
854 915
855 It is, however, possible to use them from the XS level. 916 It is, however, possible to use them from the XS level.
856 917
857 Please see the libev documentation for further details. 918 Please see the libev documentation for further details.
858 919
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877 my $async_check = EV::check sub { }; 938 my $async_check = EV::check sub { };
878 939
879 This ensures that perl gets into control for a short time to handle any 940 This ensures that perl gets into control for a short time to handle any
880 pending signals, and also ensures (slightly) slower overall operation. 941 pending signals, and also ensures (slightly) slower overall operation.
881 942
882THREADS 943ITHREADS
883 Threads are not supported by this module in any way. Perl pseudo-threads 944 Ithreads are not supported by this module in any way. Perl
884 is evil stuff and must die. As soon as Perl gains real threads I will 945 pseudo-threads is evil stuff and must die. Real threads as provided by
885 work on thread support for it. 946 Coro are fully supported (and enhanced support is available via
947 Coro::EV).
886 948
887FORK 949FORK
888 Most of the "improved" event delivering mechanisms of modern operating 950 Most of the "improved" event delivering mechanisms of modern operating
889 systems have quite a few problems with fork(2) (to put it bluntly: it is 951 systems have quite a few problems with fork(2) (to put it bluntly: it is
890 not supported and usually destructive). Libev makes it possible to work 952 not supported and usually destructive). Libev makes it possible to work
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900 962
901 On win32, there is no notion of fork so all this doesn't apply, of 963 On win32, there is no notion of fork so all this doesn't apply, of
902 course. 964 course.
903 965
904SEE ALSO 966SEE ALSO
905 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 967 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
906 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 968 DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
907 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 969 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
908 agnostic and portable event driven programming. 970 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
971 driven programming.
909 972
910AUTHOR 973AUTHOR
911 Marc Lehmann <schmorp@schmorp.de> 974 Marc Lehmann <schmorp@schmorp.de>
912 http://home.schmorp.de/ 975 http://home.schmorp.de/
913 976

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