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1NAME 1NAME
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 54
55DESCRIPTION 55DESCRIPTION
56 This module provides an interface to libev 56 This module provides an interface to libev
57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation 57 (<http://software.schmorp.de/pkg/libev.html>). While the documentation
58 below is comprehensive, one might also consult the documentation of 58 below is comprehensive, one might also consult the documentation of
59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) 59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
60 for more subtle details on watcher semantics or some discussion on the 60 perldoc EV::libev) for more subtle details on watcher semantics or some
61 available backends, or how to force a specific backend with 61 discussion on the available backends, or how to force a specific backend
62 "LIBEV_FLAGS", or just about in any case because it has much more 62 with "LIBEV_FLAGS", or just about in any case because it has much more
63 detailed information. 63 detailed information.
64 64
65 This module is very fast and scalable. It is actually so fast that you 65 This module is very fast and scalable. It is actually so fast that you
66 can use it through the AnyEvent module, stay portable to other event 66 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) 67 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 68 and still be faster than with any other event loop currently supported
69 in Perl. 69 in Perl.
70
71 MODULE EXPORTS
72 This module does not export any symbols.
70 73
71EVENT LOOPS 74EVENT LOOPS
72 EV supports multiple event loops: There is a single "default event loop" 75 EV supports multiple event loops: There is a single "default event loop"
73 that can handle everything including signals and child watchers, and any 76 that can handle everything including signals and child watchers, and any
74 number of "dynamic event loops" that can use different backends (with 77 number of "dynamic event loops" that can use different backends (with
… …
81 default loop as this is fastest (perl-wise), best supported by other 84 default loop as this is fastest (perl-wise), best supported by other
82 modules (e.g. AnyEvent or Coro) and most portable event loop. 85 modules (e.g. AnyEvent or Coro) and most portable event loop.
83 86
84 For specific programs you can create additional event loops dynamically. 87 For specific programs you can create additional event loops dynamically.
85 88
89 If you want to take advantage of kqueue (which often works properly for
90 sockets only) even though the default loop doesn't enable it, you can
91 *embed* a kqueue loop into the default loop: running the default loop
92 will then also service the kqueue loop to some extent. See the example
93 in the section about embed watchers for an example on how to achieve
94 that.
95
86 $loop = new EV::loop [$flags] 96 $loop = new EV::Loop [$flags]
87 Create a new event loop as per the specified flags. Please refer to 97 Create a new event loop as per the specified flags. Please refer to
88 the "ev_loop_new ()" function description in the libev documentation 98 the "ev_loop_new ()" function description in the libev documentation
89 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI 99 (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
90 ONS>) for more info. 100 ONS>, or locally-installed as EV::libev manpage) for more info.
91 101
92 The loop will automatically be destroyed when it is no longer 102 The loop will automatically be destroyed when it is no longer
93 referenced by any watcher and the loop object goes out of scope. 103 referenced by any watcher and the loop object goes out of scope.
94 104
95 Using "EV::FLAG_FORKCHECK" is recommended, as only the default event 105 If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
96 loop is protected by this module. 106 is recommended, as only the default event loop is protected by this
107 module. If you *are* embedding this loop in the default loop, this
108 is not necessary, as "EV::embed" automatically does the right thing
109 on fork.
97 110
98 $loop->loop_fork 111 $loop->loop_fork
99 Must be called after a fork in the child, before entering or 112 Must be called after a fork in the child, before entering or
100 continuing the event loop. An alternative is to use 113 continuing the event loop. An alternative is to use
101 "EV::FLAG_FORKCHECK" which calls this fucntion automatically, at 114 "EV::FLAG_FORKCHECK" which calls this function automatically, at
102 some performance loss (refer to the libev documentation). 115 some performance loss (refer to the libev documentation).
103 116
117 $loop->loop_verify
118 Calls "ev_verify" to make internal consistency checks (for debugging
119 libev) and abort the program if any data structures were found to be
120 corrupted.
121
104 $loop = EV::default_loop [$flags] 122 $loop = EV::default_loop [$flags]
105 Return the default loop (which is a singleton object). 123 Return the default loop (which is a singleton object). Since this
124 module already creates the default loop with default flags,
125 specifying flags here will not have any effect unless you destroy
126 the default loop first, which isn't supported. So in short: don't do
127 it, and if you break it, you get to keep the pieces.
106 128
107BASIC INTERFACE 129BASIC INTERFACE
108 $EV::DIED 130 $EV::DIED
109 Must contain a reference to a function that is called when a 131 Must contain a reference to a function that is called when a
110 callback throws an exception (with $@ containing the error). The 132 callback throws an exception (with $@ containing the error). The
… …
127 Returns the current time in (fractional) seconds since the epoch. 149 Returns the current time in (fractional) seconds since the epoch.
128 150
129 $time = EV::now 151 $time = EV::now
130 $time = $loop->now 152 $time = $loop->now
131 Returns the time the last event loop iteration has been started. 153 Returns the time the last event loop iteration has been started.
132 This is the time that (relative) timers are based on, and refering 154 This is the time that (relative) timers are based on, and referring
133 to it is usually faster then calling EV::time. 155 to it is usually faster then calling EV::time.
156
157 EV::now_update
158 $loop->now_update
159 Establishes the current time by querying the kernel, updating the
160 time returned by "EV::now" in the progress. This is a costly
161 operation and is usually done automatically within "EV::loop".
162
163 This function is rarely useful, but when some event callback runs
164 for a very long time without entering the event loop, updating
165 libev's idea of the current time is a good idea.
166
167 EV::suspend
168 $loop->suspend
169 EV::resume
170 $loop->resume
171 These two functions suspend and resume a loop, for use when the loop
172 is not used for a while and timeouts should not be processed.
173
174 A typical use case would be an interactive program such as a game:
175 When the user presses "^Z" to suspend the game and resumes it an
176 hour later it would be best to handle timeouts as if no time had
177 actually passed while the program was suspended. This can be
178 achieved by calling "suspend" in your "SIGTSTP" handler, sending
179 yourself a "SIGSTOP" and calling "resume" directly afterwards to
180 resume timer processing.
181
182 Effectively, all "timer" watchers will be delayed by the time spend
183 between "suspend" and "resume", and all "periodic" watchers will be
184 rescheduled (that is, they will lose any events that would have
185 occured while suspended).
186
187 After calling "suspend" you must not call *any* function on the
188 given loop other than "resume", and you must not call "resume"
189 without a previous call to "suspend".
190
191 Calling "suspend"/"resume" has the side effect of updating the event
192 loop time (see "now_update").
134 193
135 $backend = EV::backend 194 $backend = EV::backend
136 $backend = $loop->backend 195 $backend = $loop->backend
137 Returns an integer describing the backend used by libev 196 Returns an integer describing the backend used by libev
138 (EV::METHOD_SELECT or EV::METHOD_EPOLL). 197 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
139 198
140 EV::loop [$flags] 199 EV::loop [$flags]
141 $loop->loop ([$flags]) 200 $loop->loop ([$flags])
142 Begin checking for events and calling callbacks. It returns when a 201 Begin checking for events and calling callbacks. It returns when a
143 callback calls EV::unloop. 202 callback calls EV::unloop.
… …
157 EV::loop will return as fast as possible. 216 EV::loop will return as fast as possible.
158 217
159 $count = EV::loop_count 218 $count = EV::loop_count
160 $count = $loop->loop_count 219 $count = $loop->loop_count
161 Return the number of times the event loop has polled for new events. 220 Return the number of times the event loop has polled for new events.
162 Sometiems useful as a generation counter. 221 Sometimes useful as a generation counter.
163 222
164 EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 223 EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
165 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 224 $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
166 This function rolls together an I/O and a timer watcher for a single 225 This function rolls together an I/O and a timer watcher for a single
167 one-shot event without the need for managing a watcher object. 226 one-shot event without the need for managing a watcher object.
… …
201 $loop->set_timeout_collect_interval ($time) 260 $loop->set_timeout_collect_interval ($time)
202 These advanced functions set the minimum block interval when polling 261 These advanced functions set the minimum block interval when polling
203 for I/O events and the minimum wait interval for timer events. See 262 for I/O events and the minimum wait interval for timer events. See
204 the libev documentation at 263 the libev documentation at
205 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT 264 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
206 ROLLING_THE_EVENT_LOOP> for a more detailed discussion. 265 ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
266 detailed discussion.
267
268 $count = EV::pending_count
269 $count = $loop->pending_count
270 Returns the number of currently pending watchers.
271
272 EV::invoke_pending
273 $loop->invoke_pending
274 Invoke all currently pending watchers.
207 275
208WATCHER OBJECTS 276WATCHER OBJECTS
209 A watcher is an object that gets created to record your interest in some 277 A watcher is an object that gets created to record your interest in some
210 event. For instance, if you want to wait for STDIN to become readable, 278 event. For instance, if you want to wait for STDIN to become readable,
211 you would create an EV::io watcher for that: 279 you would create an EV::io watcher for that:
212 280
213 my $watcher = EV::io *STDIN, EV::READ, sub { 281 my $watcher = EV::io *STDIN, EV::READ, sub {
214 my ($watcher, $revents) = @_; 282 my ($watcher, $revents) = @_;
215 warn "yeah, STDIN should now be readable without blocking!\n" 283 warn "yeah, STDIN should now be readable without blocking!\n"
216 }; 284 };
217 285
218 All watchers can be active (waiting for events) or inactive (paused). 286 All watchers can be active (waiting for events) or inactive (paused).
219 Only active watchers will have their callbacks invoked. All callbacks 287 Only active watchers will have their callbacks invoked. All callbacks
220 will be called with at least two arguments: the watcher and a bitmask of 288 will be called with at least two arguments: the watcher and a bitmask of
221 received events. 289 received events.
222 290
223 Each watcher type has its associated bit in revents, so you can use the 291 Each watcher type has its associated bit in revents, so you can use the
224 same callback for multiple watchers. The event mask is named after the 292 same callback for multiple watchers. The event mask is named after the
225 type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 293 type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
226 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O 294 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
227 events (which can set both EV::READ and EV::WRITE bits), and EV::timer 295 events (which can set both EV::READ and EV::WRITE bits), and EV::timer
228 (which uses EV::TIMEOUT). 296 (which uses EV::TIMEOUT).
229 297
230 In the rare case where one wants to create a watcher but not start it at 298 In the rare case where one wants to create a watcher but not start it at
… …
315 383
316 In this case you can clear the keepalive status, which means that 384 In this case you can clear the keepalive status, which means that
317 even though your watcher is active, it won't keep "EV::loop" from 385 even though your watcher is active, it won't keep "EV::loop" from
318 returning. 386 returning.
319 387
320 The initial value for keepalive is true (enabled), and you cna 388 The initial value for keepalive is true (enabled), and you can
321 change it any time. 389 change it any time.
322 390
323 Example: Register an I/O watcher for some UDP socket but do not keep 391 Example: Register an I/O watcher for some UDP socket but do not keep
324 the event loop from running just because of that watcher. 392 the event loop from running just because of that watcher.
325 393
326 my $udp_socket = ... 394 my $udp_socket = ...
327 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; 395 my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
328 $1000udp_watcher->keepalive (0); 396 $udp_watcher->keepalive (0);
329 397
330 $loop = $w->loop 398 $loop = $w->loop
331 Return the loop that this watcher is attached to. 399 Return the loop that this watcher is attached to.
332 400
333WATCHER TYPES 401WATCHER TYPES
… …
499 Return the time that the watcher is expected to trigger next. 567 Return the time that the watcher is expected to trigger next.
500 568
501 SIGNAL WATCHERS - signal me when a signal gets signalled! 569 SIGNAL WATCHERS - signal me when a signal gets signalled!
502 $w = EV::signal $signal, $callback 570 $w = EV::signal $signal, $callback
503 $w = EV::signal_ns $signal, $callback 571 $w = EV::signal_ns $signal, $callback
572 $w = $loop->signal ($signal, $callback)
573 $w = $loop->signal_ns ($signal, $callback)
504 Call the callback when $signal is received (the signal can be 574 Call the callback when $signal is received (the signal can be
505 specified by number or by name, just as with "kill" or %SIG). 575 specified by number or by name, just as with "kill" or %SIG).
576
577 Only one event loop can grab a given signal - attempting to grab the
578 same signal from two EV loops will crash the program immediately or
579 cause data corruption.
506 580
507 EV will grab the signal for the process (the kernel only allows one 581 EV will grab the signal for the process (the kernel only allows one
508 component to receive a signal at a time) when you start a signal 582 component to receive a signal at a time) when you start a signal
509 watcher, and removes it again when you stop it. Perl does the same 583 watcher, and removes it again when you stop it. Perl does the same
510 when you add/remove callbacks to %SIG, so watch out. 584 when you add/remove callbacks to %SIG, so watch out.
… …
725 # make the dispatcher handle any new stuff 799 # make the dispatcher handle any new stuff
726 ... not shown 800 ... not shown
727 }; 801 };
728 802
729 The callbacks of the created watchers will not be called as the 803 The callbacks of the created watchers will not be called as the
730 watchers are destroyed before this cna happen (remember EV::check 804 watchers are destroyed before this can happen (remember EV::check
731 gets called first). 805 gets called first).
732 806
733 The "check_ns" variant doesn't start (activate) the newly created 807 The "check_ns" variant doesn't start (activate) the newly created
734 watcher. 808 watcher.
735 809
… …
754 embedded loop, other types of watchers might be handled in a delayed or 828 embedded loop, other types of watchers might be handled in a delayed or
755 incorrect fashion and must not be used). 829 incorrect fashion and must not be used).
756 830
757 See the libev documentation at 831 See the libev documentation at
758 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code 832 <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
759 _when_one_backend_> for more details. 833 _when_one_backend_> (locally installed as EV::libev) for more details.
760 834
761 In short, this watcher is most useful on BSD systems without working 835 In short, this watcher is most useful on BSD systems without working
762 kqueue to still be able to handle a large number of sockets: 836 kqueue to still be able to handle a large number of sockets:
763 837
764 my $socket_loop; 838 my $socket_loop;
765 839
766 # check wether we use SELECT or POLL _and_ KQUEUE is supported 840 # check wether we use SELECT or POLL _and_ KQUEUE is supported
767 if ( 841 if (
768 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) 842 (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
769 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) 843 && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
770 ) { 844 ) {
771 # use kqueue for sockets 845 # use kqueue for sockets
772 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; 846 $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
773 } 847 }
774 848
775 # use the default loop otherwise 849 # use the default loop otherwise
776 $socket_loop ||= EV::default_loop; 850 $socket_loop ||= EV::default_loop;
777 851
778 $w = EV::embed $otherloop, $callback 852 $w = EV::embed $otherloop[, $callback]
779 $w = EV::embed_ns $otherloop, $callback 853 $w = EV::embed_ns $otherloop[, $callback]
780 $w = $loop->embed ($otherloop, $callback) 854 $w = $loop->embed ($otherloop[, $callback])
781 $w = $loop->embed_ns ($otherloop, $callback) 855 $w = $loop->embed_ns ($otherloop[, $callback])
782 Call the callback when the embedded event loop ($otherloop) has any 856 Call the callback when the embedded event loop ($otherloop) has any
783 I/O activity. The $callback should alwas be specified as "undef" in 857 I/O activity. The $callback is optional: if it is missing, then the
784 this version of EV, which means the embedded event loop will be 858 embedded event loop will be managed automatically (which is
785 managed automatically. 859 recommended), otherwise you have to invoke "sweep" yourself.
786 860
787 The "embed_ns" variant doesn't start (activate) the newly created 861 The "embed_ns" variant doesn't start (activate) the newly created
788 watcher. 862 watcher.
789 863
790 ASYNC WATCHERS - how to wake up another event loop 864 ASYNC WATCHERS - how to wake up another event loop
791 Async watchers are provided by EV, but have little use in perl directly, 865 Async watchers are provided by EV, but have little use in perl directly,
792 as perl neither supports threads nor direct access to signal handlers or 866 as perl neither supports threads running in parallel nor direct access
793 other contexts where they could be of value. 867 to signal handlers or other contexts where they could be of value.
794 868
795 It is, however, possible to use them from the XS level. 869 It is, however, possible to use them from the XS level.
796 870
797 Please see the libev documentation for further details. 871 Please see the libev documentation for further details.
798 872
… …
817 my $async_check = EV::check sub { }; 891 my $async_check = EV::check sub { };
818 892
819 This ensures that perl gets into control for a short time to handle any 893 This ensures that perl gets into control for a short time to handle any
820 pending signals, and also ensures (slightly) slower overall operation. 894 pending signals, and also ensures (slightly) slower overall operation.
821 895
822THREADS 896ITHREADS
823 Threads are not supported by this module in any way. Perl pseudo-threads 897 Ithreads are not supported by this module in any way. Perl
824 is evil stuff and must die. As soon as Perl gains real threads I will 898 pseudo-threads is evil stuff and must die. Real threads as provided by
825 work on thread support for it. 899 Coro are fully supported (and enhanced support is available via
900 Coro::EV).
826 901
827FORK 902FORK
828 Most of the "improved" event delivering mechanisms of modern operating 903 Most of the "improved" event delivering mechanisms of modern operating
829 systems have quite a few problems with fork(2) (to put it bluntly: it is 904 systems have quite a few problems with fork(2) (to put it bluntly: it is
830 not supported and usually destructive). Libev makes it possible to work 905 not supported and usually destructive). Libev makes it possible to work
… …
846 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines 921 loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
847 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 922 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
848 agnostic and portable event driven programming. 923 agnostic and portable event driven programming.
849 924
850AUTHOR 925AUTHOR
851 Marc Lehmann <schmorp@schmorp.de> 926 Marc Lehmann <schmorp@schmorp.de>
852 http://home.schmorp.de/ 927 http://home.schmorp.de/
853 928

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