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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 | |
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55 | BEFORE YOU START USING THIS MODULE |
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56 | If you only need timer, I/O, signal, child and idle watchers and not the |
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57 | advanced functionality of this module, consider using AnyEvent instead, |
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58 | specifically the simplified API described in AE. |
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59 | |
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60 | When used with EV as backend, the AE API is as fast as the native EV |
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61 | API, but your programs/modules will still run with many other event |
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62 | loops. |
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63 | |
55 | DESCRIPTION |
64 | DESCRIPTION |
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 |
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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 | |
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80 | PORTING FROM EV 3.X to 4.X |
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81 | EV version 4 introduces a number of incompatible changes summarised |
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82 | here. According to the depreciation strategy used by libev, there is a |
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83 | compatibility layer in place so programs should continue to run |
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84 | unchanged (the XS interface lacks this layer, so programs using that one |
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85 | need to be updated). |
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86 | |
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87 | This compatibility layer will be switched off in some future release. |
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88 | |
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89 | All changes relevant to Perl are renames of symbols, functions and |
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90 | methods: |
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91 | |
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92 | EV::loop => EV::run |
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93 | EV::LOOP_NONBLOCK => EV::RUN_NOWAIT |
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94 | EV::LOOP_ONESHOT => EV::RUN_ONCE |
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95 | |
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96 | EV::unloop => EV::break |
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97 | EV::UNLOOP_CANCEL => EV::BREAK_CANCEL |
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98 | EV::UNLOOP_ONE => EV::BREAK_ONE |
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99 | EV::UNLOOP_ALL => EV::BREAK_ALL |
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100 | |
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101 | EV::TIMEOUT => EV::TIMER |
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102 | |
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103 | EV::loop_count => EV::iteration |
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104 | EV::loop_depth => EV::depth |
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105 | EV::loop_verify => EV::verify |
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106 | |
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107 | The loop object methods corresponding to the functions above have been |
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108 | similarly renamed. |
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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 | |
74 | EVENT LOOPS |
113 | EVENT 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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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). |
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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 | |
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758 | $w = $loop->check_ns ($callback) |
796 | $w = $loop->check_ns ($callback) |
759 | 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 |
760 | has gathered events), but before any other callbacks have been |
798 | has gathered events), but before any other callbacks have been |
761 | invoked. |
799 | invoked. |
762 | |
800 | |
763 | 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 |
764 | mainloop: You register a prepare callback and in there, you create |
802 | mainloop: You register a prepare callback and in there, you create |
765 | 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 |
766 | real-world example of integrating Net::SNMP (with some details left |
804 | real-world example of integrating Net::SNMP (with some details left |
767 | out): |
805 | out): |
768 | |
806 | |
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804 | watchers are destroyed before this can happen (remember EV::check |
842 | watchers are destroyed before this can happen (remember EV::check |
805 | gets called first). |
843 | gets called first). |
806 | |
844 | |
807 | The "check_ns" variant doesn't start (activate) the newly created |
845 | The "check_ns" variant doesn't start (activate) the newly created |
808 | watcher. |
846 | watcher. |
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847 | |
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848 | EV::CHECK constant issues |
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849 | Like all other watcher types, there is a bitmask constant for use in |
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850 | $revents and other places. The "EV::CHECK" is special as it has the |
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851 | same name as the "CHECK" sub called by Perl. This doesn't cause big |
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852 | issues on newer perls (beginning with 5.8.9), but it means thatthe |
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853 | constant must be *inlined*, i.e. runtime calls will not work. That |
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854 | means that as long as you always "use EV" and then "EV::CHECK" you |
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855 | are on the safe side. |
809 | |
856 | |
810 | 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 |
811 | Fork watchers are called when a "fork ()" was detected. The invocation |
858 | Fork watchers are called when a "fork ()" was detected. The invocation |
812 | 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 |
813 | are being called, and only in the child after the fork. |
860 | are being called, and only in the child after the fork. |