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Revision 1.33 by root, Fri Jul 17 14:49:33 2009 UTC vs.
Revision 1.38 by root, Mon Oct 25 11:30:45 2010 UTC

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
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.
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
59 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or 68 libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
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"
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
290 329
291 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
292 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
293 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,
294 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
295 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).
296 (which uses EV::TIMEOUT).
297 335
298 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
299 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
300 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.
301 339
366 the watcher isn't pending it does nothing and returns 0. 404 the watcher isn't pending it does nothing and returns 0.
367 405
368 $previous_state = $w->keepalive ($bool) 406 $previous_state = $w->keepalive ($bool)
369 Normally, "EV::loop" will return when there are no active watchers 407 Normally, "EV::loop" will return when there are no active watchers
370 (which is a "deadlock" because no progress can be made anymore). 408 (which is a "deadlock" because no progress can be made anymore).
371 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
372 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
373 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
374 for their task :). 412 for their task :).
375 413
376 Sometimes, however, this gets in your way, for example when the 414 Sometimes, however, this gets in your way, for example when the
567 Return the time that the watcher is expected to trigger next. 605 Return the time that the watcher is expected to trigger next.
568 606
569 SIGNAL WATCHERS - signal me when a signal gets signalled! 607 SIGNAL WATCHERS - signal me when a signal gets signalled!
570 $w = EV::signal $signal, $callback 608 $w = EV::signal $signal, $callback
571 $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)
572 Call the callback when $signal is received (the signal can be 612 Call the callback when $signal is received (the signal can be
573 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.
574 618
575 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
576 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
577 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
578 when you add/remove callbacks to %SIG, so watch out. 622 when you add/remove callbacks to %SIG, so watch out.
752 $w = $loop->check_ns ($callback) 796 $w = $loop->check_ns ($callback)
753 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
754 has gathered events), but before any other callbacks have been 798 has gathered events), but before any other callbacks have been
755 invoked. 799 invoked.
756 800
757 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
758 mainloop: You register a prepare callback and in there, you create 802 mainloop: You register a prepare callback and in there, you create
759 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
760 real-world example of integrating Net::SNMP (with some details left 804 real-world example of integrating Net::SNMP (with some details left
761 out): 805 out):
762 806
798 watchers are destroyed before this can happen (remember EV::check 842 watchers are destroyed before this can happen (remember EV::check
799 gets called first). 843 gets called first).
800 844
801 The "check_ns" variant doesn't start (activate) the newly created 845 The "check_ns" variant doesn't start (activate) the newly created
802 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.
803 856
804 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
805 Fork watchers are called when a "fork ()" was detected. The invocation 858 Fork watchers are called when a "fork ()" was detected. The invocation
806 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
807 are being called, and only in the child after the fork. 860 are being called, and only in the child after the fork.
909 962
910 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
911 course. 964 course.
912 965
913SEE ALSO 966SEE ALSO
914 EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event 967 EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
915 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
916 with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop 969 Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
917 agnostic and portable event driven programming. 970 (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
971 driven programming.
918 972
919AUTHOR 973AUTHOR
920 Marc Lehmann <schmorp@schmorp.de> 974 Marc Lehmann <schmorp@schmorp.de>
921 http://home.schmorp.de/ 975 http://home.schmorp.de/
922 976

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