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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 | |
5 | SYNOPSIS |
5 | SYNOPSIS |
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 | |
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24 | # IO |
23 | |
25 | |
24 | # IO |
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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, 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 | |
55 | DESCRIPTION |
55 | DESCRIPTION |
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://cvs.schmorp.de/libev/ev.html>) for more subtle |
59 | libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle |
60 | details on watcher semantics or some discussion on the available |
60 | details on watcher semantics or some discussion on the available |
61 | backends, or how to force a specific backend with "LIBEV_FLAGS". |
61 | backends, or how to force a specific backend with "LIBEV_FLAGS", or just |
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62 | about in any case because it has much more detailed information. |
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63 | |
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64 | EVENT LOOPS |
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65 | EV supports multiple event loops: There is a single "default event loop" |
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66 | that can handle everything including signals and child watchers, and any |
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67 | number of "dynamic event loops" that can use different backends (with |
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68 | various limitations), but no child and signal watchers. |
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69 | |
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70 | You do not have to do anything to create the default event loop: When |
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71 | the module is loaded a suitable backend is selected on the premise of |
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72 | selecting a working backend (which for example rules out kqueue on most |
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73 | BSDs). Modules should, unless they have "special needs" always use the |
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74 | default loop as this is fastest (perl-wise), best supported by other |
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75 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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76 | |
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77 | For specific programs you can create additional event loops dynamically. |
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78 | |
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79 | $loop = new EV::loop [$flags] |
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80 | Create a new event loop as per the specified flags. Please refer to |
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81 | the "ev_loop_new ()" function description in the libev documentation |
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82 | (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI |
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83 | ONS>) for more info. |
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84 | |
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85 | The loop will automatically be destroyed when it is no longer |
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86 | referenced by any watcher and the loop object goes out of scope. |
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87 | |
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88 | Using "EV::FLAG_FORKCHECK" is recommended, as only the default event |
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89 | loop is protected by this module. |
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90 | |
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91 | $loop->loop_fork |
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92 | Must be called after a fork in the child, before entering or |
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93 | continuing the event loop. An alternative is to use |
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94 | "EV::FLAG_FORKCHECK" which calls this fucntion automatically, at |
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95 | some performance loss (refer to the libev documentation). |
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96 | |
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97 | $loop = EV::default_loop [$flags] |
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98 | Return the default loop (which is a singleton object). |
62 | |
99 | |
63 | BASIC INTERFACE |
100 | BASIC INTERFACE |
64 | $EV::DIED |
101 | $EV::DIED |
65 | Must contain a reference to a function that is called when a |
102 | Must contain a reference to a function that is called when a |
66 | callback throws an exception (with $@ containing thr error). The |
103 | callback throws an exception (with $@ containing the error). The |
67 | default prints an informative message and continues. |
104 | default prints an informative message and continues. |
68 | |
105 | |
69 | If this callback throws an exception it will be silently ignored. |
106 | If this callback throws an exception it will be silently ignored. |
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107 | |
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108 | $flags = EV::supported_backends |
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109 | $flags = EV::recommended_backends |
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110 | $flags = EV::embeddable_backends |
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111 | Returns the set (see "EV::BACKEND_*" flags) of backends supported by |
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112 | this instance of EV, the set of recommended backends (supposed to be |
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113 | good) for this platform and the set of embeddable backends (see |
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114 | EMBED WATCHERS). |
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115 | |
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116 | EV::sleep $seconds |
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117 | Block the process for the given number of (fractional) seconds. |
70 | |
118 | |
71 | $time = EV::time |
119 | $time = EV::time |
72 | Returns the current time in (fractional) seconds since the epoch. |
120 | Returns the current time in (fractional) seconds since the epoch. |
73 | |
121 | |
74 | $time = EV::now |
122 | $time = EV::now |
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123 | $time = $loop->now |
75 | Returns the time the last event loop iteration has been started. |
124 | Returns the time the last event loop iteration has been started. |
76 | This is the time that (relative) timers are based on, and refering |
125 | This is the time that (relative) timers are based on, and refering |
77 | to it is usually faster then calling EV::time. |
126 | to it is usually faster then calling EV::time. |
78 | |
127 | |
79 | $method = EV::method |
128 | $backend = EV::backend |
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129 | $backend = $loop->backend |
80 | Returns an integer describing the backend used by libev |
130 | Returns an integer describing the backend used by libev |
81 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
131 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
82 | |
132 | |
83 | EV::loop [$flags] |
133 | EV::loop [$flags] |
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134 | $loop->loop ([$flags]) |
84 | Begin checking for events and calling callbacks. It returns when a |
135 | Begin checking for events and calling callbacks. It returns when a |
85 | callback calls EV::unloop. |
136 | callback calls EV::unloop. |
86 | |
137 | |
87 | The $flags argument can be one of the following: |
138 | The $flags argument can be one of the following: |
88 | |
139 | |
89 | 0 as above |
140 | 0 as above |
90 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
141 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
91 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
142 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
92 | |
143 | |
93 | EV::unloop [$how] |
144 | EV::unloop [$how] |
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145 | $loop->unloop ([$how]) |
94 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
146 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
95 | makes the innermost call to EV::loop return. |
147 | makes the innermost call to EV::loop return. |
96 | |
148 | |
97 | When called with an argument of EV::UNLOOP_ALL, all calls to |
149 | When called with an argument of EV::UNLOOP_ALL, all calls to |
98 | EV::loop will return as fast as possible. |
150 | EV::loop will return as fast as possible. |
99 | |
151 | |
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152 | $count = EV::loop_count |
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153 | $count = $loop->loop_count |
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154 | Return the number of times the event loop has polled for new events. |
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155 | Sometiems useful as a generation counter. |
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156 | |
100 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
157 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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158 | $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
101 | This function rolls together an I/O and a timer watcher for a single |
159 | This function rolls together an I/O and a timer watcher for a single |
102 | one-shot event without the need for managing a watcher object. |
160 | one-shot event without the need for managing a watcher object. |
103 | |
161 | |
104 | If $fh_or_undef is a filehandle or file descriptor, then $events |
162 | If $fh_or_undef is a filehandle or file descriptor, then $events |
105 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
163 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
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110 | If timeout is "undef" or negative, then there will be no timeout. |
168 | If timeout is "undef" or negative, then there will be no timeout. |
111 | Otherwise a EV::timer with this value will be started. |
169 | Otherwise a EV::timer with this value will be started. |
112 | |
170 | |
113 | When an error occurs or either the timeout or I/O watcher triggers, |
171 | When an error occurs or either the timeout or I/O watcher triggers, |
114 | then the callback will be called with the received event set (in |
172 | then the callback will be called with the received event set (in |
115 | general you can expect it to be a combination of "EV:ERROR", |
173 | general you can expect it to be a combination of "EV::ERROR", |
116 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
174 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
117 | |
175 | |
118 | EV::once doesn't return anything: the watchers stay active till |
176 | EV::once doesn't return anything: the watchers stay active till |
119 | either of them triggers, then they will be stopped and freed, and |
177 | either of them triggers, then they will be stopped and freed, and |
120 | the callback invoked. |
178 | the callback invoked. |
121 | |
179 | |
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180 | EV::feed_fd_event ($fd, $revents) |
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181 | $loop->feed_fd_event ($fd, $revents) |
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182 | Feed an event on a file descriptor into EV. EV will react to this |
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183 | call as if the readyness notifications specified by $revents (a |
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184 | combination of "EV::READ" and "EV::WRITE") happened on the file |
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185 | descriptor $fd. |
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186 | |
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187 | EV::feed_signal_event ($signal) |
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188 | Feed a signal event into EV. EV will react to this call as if the |
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189 | signal specified by $signal had occured. |
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190 | |
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191 | EV::set_io_collect_interval $time |
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192 | $loop->set_io_collect_interval ($time) |
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193 | EV::set_timeout_collect_interval $time |
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194 | $loop->set_timeout_collect_interval ($time) |
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195 | These advanced functions set the minimum block interval when polling |
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196 | for I/O events and the minimum wait interval for timer events. See |
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197 | the libev documentation at |
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198 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT |
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199 | ROLLING_THE_EVENT_LOOP> for a more detailed discussion. |
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200 | |
122 | WATCHER OBJECTS |
201 | WATCHER OBJECTS |
123 | A watcher is an object that gets created to record your interest in some |
202 | A watcher is an object that gets created to record your interest in some |
124 | event. For instance, if you want to wait for STDIN to become readable, |
203 | event. For instance, if you want to wait for STDIN to become readable, |
125 | you would create an EV::io watcher for that: |
204 | you would create an EV::io watcher for that: |
126 | |
205 | |
127 | my $watcher = EV::io *STDIN, EV::READ, sub { |
206 | my $watcher = EV::io *STDIN, EV::READ, sub { |
128 | my ($watcher, $revents) = @_; |
207 | my ($watcher, $revents) = @_; |
129 | warn "yeah, STDIN should not be readable without blocking!\n" |
208 | warn "yeah, STDIN should now be readable without blocking!\n" |
130 | }; |
209 | }; |
131 | |
210 | |
132 | All watchers can be active (waiting for events) or inactive (paused). |
211 | All watchers can be active (waiting for events) or inactive (paused). |
133 | Only active watchers will have their callbacks invoked. All callbacks |
212 | Only active watchers will have their callbacks invoked. All callbacks |
134 | will be called with at least two arguments: the watcher and a bitmask of |
213 | will be called with at least two arguments: the watcher and a bitmask of |
135 | received events. |
214 | received events. |
136 | |
215 | |
137 | Each watcher type has its associated bit in revents, so you can use the |
216 | Each watcher type has its associated bit in revents, so you can use the |
138 | same callback for multiple watchers. The event mask is named after the |
217 | same callback for multiple watchers. The event mask is named after the |
139 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
218 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
140 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO |
219 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
141 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
220 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
142 | (which uses EV::TIMEOUT). |
221 | (which uses EV::TIMEOUT). |
143 | |
222 | |
144 | In the rare case where one wants to create a watcher but not start it at |
223 | In the rare case where one wants to create a watcher but not start it at |
145 | the same time, each constructor has a variant with a trailing "_ns" in |
224 | the same time, each constructor has a variant with a trailing "_ns" in |
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163 | stopped watchers). |
242 | stopped watchers). |
164 | |
243 | |
165 | $w->stop |
244 | $w->stop |
166 | Stop a watcher if it is active. Also clear any pending events |
245 | Stop a watcher if it is active. Also clear any pending events |
167 | (events that have been received but that didn't yet result in a |
246 | (events that have been received but that didn't yet result in a |
168 | callback invocation), regardless of wether the watcher was active or |
247 | callback invocation), regardless of whether the watcher was active |
169 | not. |
248 | or not. |
170 | |
249 | |
171 | $bool = $w->is_active |
250 | $bool = $w->is_active |
172 | Returns true if the watcher is active, false otherwise. |
251 | Returns true if the watcher is active, false otherwise. |
173 | |
252 | |
174 | $current_data = $w->data |
253 | $current_data = $w->data |
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197 | The default priority of any newly-created watcher is 0. |
276 | The default priority of any newly-created watcher is 0. |
198 | |
277 | |
199 | Note that the priority semantics have not yet been fleshed out and |
278 | Note that the priority semantics have not yet been fleshed out and |
200 | are subject to almost certain change. |
279 | are subject to almost certain change. |
201 | |
280 | |
202 | $w->trigger ($revents) |
281 | $w->invoke ($revents) |
203 | Call the callback *now* with the given event mask. |
282 | Call the callback *now* with the given event mask. |
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283 | |
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284 | $w->feed_event ($revents) |
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285 | Feed some events on this watcher into EV. EV will react to this call |
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286 | as if the watcher had received the given $revents mask. |
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287 | |
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288 | $revents = $w->clear_pending |
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289 | If the watcher is pending, this function clears its pending status |
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290 | and returns its $revents bitset (as if its callback was invoked). If |
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291 | the watcher isn't pending it does nothing and returns 0. |
204 | |
292 | |
205 | $previous_state = $w->keepalive ($bool) |
293 | $previous_state = $w->keepalive ($bool) |
206 | Normally, "EV::loop" will return when there are no active watchers |
294 | Normally, "EV::loop" will return when there are no active watchers |
207 | (which is a "deadlock" because no progress can be made anymore). |
295 | (which is a "deadlock" because no progress can be made anymore). |
208 | This is convinient because it allows you to start your watchers (and |
296 | This is convinient because it allows you to start your watchers (and |
209 | your jobs), call "EV::loop" once and when it returns you know that |
297 | your jobs), call "EV::loop" once and when it returns you know that |
210 | all your jobs are finished (or they forgot to register some watchers |
298 | all your jobs are finished (or they forgot to register some watchers |
211 | for their task :). |
299 | for their task :). |
212 | |
300 | |
213 | Sometimes, however, this gets in your way, for example when you the |
301 | Sometimes, however, this gets in your way, for example when the |
214 | module that calls "EV::loop" (usually the main program) is not the |
302 | module that calls "EV::loop" (usually the main program) is not the |
215 | same module as a long-living watcher (for example a DNS client |
303 | same module as a long-living watcher (for example a DNS client |
216 | module written by somebody else even). Then you might want any |
304 | module written by somebody else even). Then you might want any |
217 | outstanding requests to be handled, but you would not want to keep |
305 | outstanding requests to be handled, but you would not want to keep |
218 | "EV::loop" from returning just because you happen to have this |
306 | "EV::loop" from returning just because you happen to have this |
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223 | returning. |
311 | returning. |
224 | |
312 | |
225 | The initial value for keepalive is true (enabled), and you cna |
313 | The initial value for keepalive is true (enabled), and you cna |
226 | change it any time. |
314 | change it any time. |
227 | |
315 | |
228 | Example: Register an IO watcher for some UDP socket but do not keep |
316 | Example: Register an I/O watcher for some UDP socket but do not keep |
229 | the event loop from running just because of that watcher. |
317 | the event loop from running just because of that watcher. |
230 | |
318 | |
231 | my $udp_socket = ... |
319 | my $udp_socket = ... |
232 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
320 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
233 | $udp_watcher->keepalive (0); |
321 | $1000udp_watcher->keepalive (0); |
234 | |
322 | |
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323 | $loop = $w->loop |
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324 | Return the loop that this watcher is attached to. |
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325 | |
235 | WATCHER TYPES |
326 | WATCHER TYPES |
236 | Each of the following subsections describes a single watcher type. |
327 | Each of the following subsections describes a single watcher type. |
237 | |
328 | |
238 | IO WATCHERS - is this file descriptor readable or writable? |
329 | I/O WATCHERS - is this file descriptor readable or writable? |
239 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
330 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
240 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
331 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
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332 | $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
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333 | $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
241 | As long as the returned watcher object is alive, call the $callback |
334 | As long as the returned watcher object is alive, call the $callback |
242 | when at least one of events specified in $eventmask occurs. |
335 | when at least one of events specified in $eventmask occurs. |
243 | |
336 | |
244 | The $eventmask can be one or more of these constants ORed together: |
337 | The $eventmask can be one or more of these constants ORed together: |
245 | |
338 | |
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262 | Returns the previously set event mask and optionally set a new one. |
355 | Returns the previously set event mask and optionally set a new one. |
263 | |
356 | |
264 | TIMER WATCHERS - relative and optionally repeating timeouts |
357 | TIMER WATCHERS - relative and optionally repeating timeouts |
265 | $w = EV::timer $after, $repeat, $callback |
358 | $w = EV::timer $after, $repeat, $callback |
266 | $w = EV::timer_ns $after, $repeat, $callback |
359 | $w = EV::timer_ns $after, $repeat, $callback |
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360 | $w = $loop->timer ($after, $repeat, $callback) |
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361 | $w = $loop->timer_ns ($after, $repeat, $callback) |
267 | Calls the callback after $after seconds (which may be fractional). |
362 | Calls the callback after $after seconds (which may be fractional). |
268 | If $repeat is non-zero, the timer will be restarted (with the |
363 | If $repeat is non-zero, the timer will be restarted (with the |
269 | $repeat value as $after) after the callback returns. |
364 | $repeat value as $after) after the callback returns. |
270 | |
365 | |
271 | This means that the callback would be called roughly after $after |
366 | This means that the callback would be called roughly after $after |
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307 | method on the timeout. |
402 | method on the timeout. |
308 | |
403 | |
309 | PERIODIC WATCHERS - to cron or not to cron? |
404 | PERIODIC WATCHERS - to cron or not to cron? |
310 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
405 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
311 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
406 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
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407 | $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
|
|
408 | $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
312 | Similar to EV::timer, but is not based on relative timeouts but on |
409 | Similar to EV::timer, but is not based on relative timeouts but on |
313 | absolute times. Apart from creating "simple" timers that trigger |
410 | absolute times. Apart from creating "simple" timers that trigger |
314 | "at" the specified time, it can also be used for non-drifting |
411 | "at" the specified time, it can also be used for non-drifting |
315 | absolute timers and more complex, cron-like, setups that are not |
412 | absolute timers and more complex, cron-like, setups that are not |
316 | adversely affected by time jumps (i.e. when the system clock is |
413 | adversely affected by time jumps (i.e. when the system clock is |
317 | changed by explicit date -s or other means such as ntpd). It is also |
414 | changed by explicit date -s or other means such as ntpd). It is also |
318 | the most complex watcher type in EV. |
415 | the most complex watcher type in EV. |
319 | |
416 | |
320 | It has three distinct "modes": |
417 | It has three distinct "modes": |
321 | |
418 | |
322 | * absolute timer ($interval = $reschedule_cb = 0) |
419 | * absolute timer ($interval = $reschedule_cb = 0) |
|
|
420 | |
323 | This time simply fires at the wallclock time $at and doesn't |
421 | This time simply fires at the wallclock time $at and doesn't |
324 | repeat. It will not adjust when a time jump occurs, that is, if |
422 | repeat. It will not adjust when a time jump occurs, that is, if |
325 | it is to be run at January 1st 2011 then it will run when the |
423 | it is to be run at January 1st 2011 then it will run when the |
326 | system time reaches or surpasses this time. |
424 | system time reaches or surpasses this time. |
327 | |
425 | |
328 | * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
426 | * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
427 | |
329 | In this mode the watcher will always be scheduled to time out at |
428 | In this mode the watcher will always be scheduled to time out at |
330 | the next "$at + N * $interval" time (for some integer N) and |
429 | the next "$at + N * $interval" time (for some integer N) and |
331 | then repeat, regardless of any time jumps. |
430 | then repeat, regardless of any time jumps. |
332 | |
431 | |
333 | This can be used to create timers that do not drift with respect |
432 | This can be used to create timers that do not drift with respect |
… | |
… | |
342 | Another way to think about it (for the mathematically inclined) |
441 | Another way to think about it (for the mathematically inclined) |
343 | is that EV::periodic will try to run the callback in this mode |
442 | is that EV::periodic will try to run the callback in this mode |
344 | at the next possible time where "$time = $at (mod $interval)", |
443 | at the next possible time where "$time = $at (mod $interval)", |
345 | regardless of any time jumps. |
444 | regardless of any time jumps. |
346 | |
445 | |
347 | * manual reschedule mode ($reschedule_cb = coderef) |
446 | * manual reschedule mode ($reschedule_cb = coderef) |
|
|
447 | |
348 | In this mode $interval and $at are both being ignored. Instead, |
448 | In this mode $interval and $at are both being ignored. Instead, |
349 | each time the periodic watcher gets scheduled, the reschedule |
449 | each time the periodic watcher gets scheduled, the reschedule |
350 | callback ($reschedule_cb) will be called with the watcher as |
450 | callback ($reschedule_cb) will be called with the watcher as |
351 | first, and the current time as second argument. |
451 | first, and the current time as second argument. |
352 | |
452 | |
… | |
… | |
384 | be called at any time. |
484 | be called at any time. |
385 | |
485 | |
386 | $w->again |
486 | $w->again |
387 | Simply stops and starts the watcher again. |
487 | Simply stops and starts the watcher again. |
388 | |
488 | |
|
|
489 | $time = $w->at |
|
|
490 | Return the time that the watcher is expected to trigger next. |
|
|
491 | |
389 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
492 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
390 | $w = EV::signal $signal, $callback |
493 | $w = EV::signal $signal, $callback |
391 | $w = EV::signal_ns $signal, $callback |
494 | $w = EV::signal_ns $signal, $callback |
392 | Call the callback when $signal is received (the signal can be |
495 | Call the callback when $signal is received (the signal can be |
393 | specified by number or by name, just as with "kill" or %SIG). |
496 | specified by number or by name, just as with "kill" or %SIG). |
… | |
… | |
410 | $old_signum = $w->signal ($new_signal) |
513 | $old_signum = $w->signal ($new_signal) |
411 | Returns the previously set signal (always as a number not name) and |
514 | Returns the previously set signal (always as a number not name) and |
412 | optionally set a new one. |
515 | optionally set a new one. |
413 | |
516 | |
414 | CHILD WATCHERS - watch out for process status changes |
517 | CHILD WATCHERS - watch out for process status changes |
415 | $w = EV::child $pid, $callback |
518 | $w = EV::child $pid, $trace, $callback |
416 | $w = EV::child_ns $pid, $callback |
519 | $w = EV::child_ns $pid, $trace, $callback |
|
|
520 | $w = $loop->child ($pid, $trace, $callback) |
|
|
521 | $w = $loop->child_ns ($pid, $trace, $callback) |
417 | Call the callback when a status change for pid $pid (or any pid if |
522 | Call the callback when a status change for pid $pid (or any pid if |
418 | $pid is 0) has been received. More precisely: when the process |
523 | $pid is 0) has been received (a status change happens when the |
|
|
524 | process terminates or is killed, or, when trace is true, |
|
|
525 | additionally when it is stopped or continued). More precisely: when |
419 | receives a "SIGCHLD", EV will fetch the outstanding exit/wait status |
526 | the process receives a "SIGCHLD", EV will fetch the outstanding |
420 | for all changed/zombie children and call the callback. |
527 | exit/wait status for all changed/zombie children and call the |
|
|
528 | callback. |
421 | |
529 | |
422 | It is valid (and fully supported) to install a child watcher after a |
530 | It is valid (and fully supported) to install a child watcher after a |
423 | child has exited but before the event loop has started its next |
531 | child has exited but before the event loop has started its next |
424 | iteration (for example, first you "fork", then the new child process |
532 | iteration (for example, first you "fork", then the new child process |
425 | might exit, and only then do you install a child watcher in the |
533 | might exit, and only then do you install a child watcher in the |
… | |
… | |
432 | be called. |
540 | be called. |
433 | |
541 | |
434 | The "child_ns" variant doesn't start (activate) the newly created |
542 | The "child_ns" variant doesn't start (activate) the newly created |
435 | watcher. |
543 | watcher. |
436 | |
544 | |
437 | $w->set ($pid) |
545 | $w->set ($pid, $trace) |
438 | Reconfigures the watcher, see the constructor above for details. Can |
546 | Reconfigures the watcher, see the constructor above for details. Can |
439 | be called at any time. |
547 | be called at any time. |
440 | |
548 | |
441 | $current_pid = $w->pid |
549 | $current_pid = $w->pid |
442 | $old_pid = $w->pid ($new_pid) |
|
|
443 | Returns the previously set process id and optionally set a new one. |
550 | Returns the previously set process id and optionally set a new one. |
444 | |
551 | |
445 | $exit_status = $w->rstatus |
552 | $exit_status = $w->rstatus |
446 | Return the exit/wait status (as returned by waitpid, see the waitpid |
553 | Return the exit/wait status (as returned by waitpid, see the waitpid |
447 | entry in perlfunc). |
554 | entry in perlfunc). |
… | |
… | |
451 | a watcher for all pids). |
558 | a watcher for all pids). |
452 | |
559 | |
453 | STAT WATCHERS - did the file attributes just change? |
560 | STAT WATCHERS - did the file attributes just change? |
454 | $w = EV::stat $path, $interval, $callback |
561 | $w = EV::stat $path, $interval, $callback |
455 | $w = EV::stat_ns $path, $interval, $callback |
562 | $w = EV::stat_ns $path, $interval, $callback |
|
|
563 | $w = $loop->stat ($path, $interval, $callback) |
|
|
564 | $w = $loop->stat_ns ($path, $interval, $callback) |
456 | Call the callback when a file status change has been detected on |
565 | Call the callback when a file status change has been detected on |
457 | $path. The $path does not need to exist, changing from "path exists" |
566 | $path. The $path does not need to exist, changing from "path exists" |
458 | to "path does not exist" is a status change like any other. |
567 | to "path does not exist" is a status change like any other. |
459 | |
568 | |
460 | The $interval is a recommended polling interval for systems where |
569 | The $interval is a recommended polling interval for systems where |
… | |
… | |
468 | resource-intensive. |
577 | resource-intensive. |
469 | |
578 | |
470 | The "stat_ns" variant doesn't start (activate) the newly created |
579 | The "stat_ns" variant doesn't start (activate) the newly created |
471 | watcher. |
580 | watcher. |
472 | |
581 | |
|
|
582 | ... = $w->stat |
|
|
583 | This call is very similar to the perl "stat" built-in: It stats |
|
|
584 | (using "lstat") the path specified in the watcher and sets perls |
|
|
585 | stat cache (as well as EV's idea of the current stat values) to the |
|
|
586 | values found. |
|
|
587 | |
|
|
588 | In scalar context, a boolean is return indicating success or failure |
|
|
589 | of the stat. In list context, the same 13-value list as with stat is |
|
|
590 | returned (except that the blksize and blocks fields are not |
|
|
591 | reliable). |
|
|
592 | |
|
|
593 | In the case of an error, errno is set to "ENOENT" (regardless of the |
|
|
594 | actual error value) and the "nlink" value is forced to zero (if the |
|
|
595 | stat was successful then nlink is guaranteed to be non-zero). |
|
|
596 | |
|
|
597 | See also the next two entries for more info. |
|
|
598 | |
|
|
599 | ... = $w->attr |
|
|
600 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
601 | the values most recently detected by EV. See the next entry for more |
|
|
602 | info. |
|
|
603 | |
|
|
604 | ... = $w->prev |
|
|
605 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
606 | the previous set of values, before the change. |
|
|
607 | |
|
|
608 | That is, when the watcher callback is invoked, "$w->prev" will be |
|
|
609 | set to the values found *before* a change was detected, while |
|
|
610 | "$w->attr" returns the values found leading to the change detection. |
|
|
611 | The difference (if any) between "prev" and "attr" is what triggered |
|
|
612 | the callback. |
|
|
613 | |
|
|
614 | If you did something to the filesystem object and do not want to |
|
|
615 | trigger yet another change, you can call "stat" to update EV's idea |
|
|
616 | of what the current attributes are. |
|
|
617 | |
473 | $w->set ($path, $interval) |
618 | $w->set ($path, $interval) |
474 | Reconfigures the watcher, see the constructor above for details. Can |
619 | Reconfigures the watcher, see the constructor above for details. Can |
475 | be called at any time. |
620 | be called at any time. |
476 | |
621 | |
477 | $current_path = $w->path |
622 | $current_path = $w->path |
… | |
… | |
484 | Can be used to query the actual interval used. |
629 | Can be used to query the actual interval used. |
485 | |
630 | |
486 | IDLE WATCHERS - when you've got nothing better to do... |
631 | IDLE WATCHERS - when you've got nothing better to do... |
487 | $w = EV::idle $callback |
632 | $w = EV::idle $callback |
488 | $w = EV::idle_ns $callback |
633 | $w = EV::idle_ns $callback |
|
|
634 | $w = $loop->idle ($callback) |
|
|
635 | $w = $loop->idle_ns ($callback) |
489 | Call the callback when there are no pending io, timer/periodic, |
636 | Call the callback when there are no other pending watchers of the |
490 | signal or child events, i.e. when the process is idle. |
637 | same or higher priority (excluding check, prepare and other idle |
|
|
638 | watchers of the same or lower priority, of course). They are called |
|
|
639 | idle watchers because when the watcher is the highest priority |
|
|
640 | pending event in the process, the process is considered to be idle |
|
|
641 | at that priority. |
|
|
642 | |
|
|
643 | If you want a watcher that is only ever called when *no* other |
|
|
644 | events are outstanding you have to set the priority to "EV::MINPRI". |
491 | |
645 | |
492 | The process will not block as long as any idle watchers are active, |
646 | The process will not block as long as any idle watchers are active, |
493 | and they will be called repeatedly until stopped. |
647 | and they will be called repeatedly until stopped. |
|
|
648 | |
|
|
649 | For example, if you have idle watchers at priority 0 and 1, and an |
|
|
650 | I/O watcher at priority 0, then the idle watcher at priority 1 and |
|
|
651 | the I/O watcher will always run when ready. Only when the idle |
|
|
652 | watcher at priority 1 is stopped and the I/O watcher at priority 0 |
|
|
653 | is not pending with the 0-priority idle watcher be invoked. |
494 | |
654 | |
495 | The "idle_ns" variant doesn't start (activate) the newly created |
655 | The "idle_ns" variant doesn't start (activate) the newly created |
496 | watcher. |
656 | watcher. |
497 | |
657 | |
498 | PREPARE WATCHERS - customise your event loop! |
658 | PREPARE WATCHERS - customise your event loop! |
499 | $w = EV::prepare $callback |
659 | $w = EV::prepare $callback |
500 | $w = EV::prepare_ns $callback |
660 | $w = EV::prepare_ns $callback |
|
|
661 | $w = $loop->prepare ($callback) |
|
|
662 | $w = $loop->prepare_ns ($callback) |
501 | Call the callback just before the process would block. You can still |
663 | Call the callback just before the process would block. You can still |
502 | create/modify any watchers at this point. |
664 | create/modify any watchers at this point. |
503 | |
665 | |
504 | See the EV::check watcher, below, for explanations and an example. |
666 | See the EV::check watcher, below, for explanations and an example. |
505 | |
667 | |
… | |
… | |
507 | watcher. |
669 | watcher. |
508 | |
670 | |
509 | CHECK WATCHERS - customise your event loop even more! |
671 | CHECK WATCHERS - customise your event loop even more! |
510 | $w = EV::check $callback |
672 | $w = EV::check $callback |
511 | $w = EV::check_ns $callback |
673 | $w = EV::check_ns $callback |
|
|
674 | $w = $loop->check ($callback) |
|
|
675 | $w = $loop->check_ns ($callback) |
512 | Call the callback just after the process wakes up again (after it |
676 | Call the callback just after the process wakes up again (after it |
513 | has gathered events), but before any other callbacks have been |
677 | has gathered events), but before any other callbacks have been |
514 | invoked. |
678 | invoked. |
515 | |
679 | |
516 | This is used to integrate other event-based software into the EV |
680 | This is used to integrate other event-based software into the EV |
… | |
… | |
527 | or return; |
691 | or return; |
528 | |
692 | |
529 | # make the dispatcher handle any outstanding stuff |
693 | # make the dispatcher handle any outstanding stuff |
530 | ... not shown |
694 | ... not shown |
531 | |
695 | |
532 | # create an IO watcher for each and every socket |
696 | # create an I/O watcher for each and every socket |
533 | @snmp_watcher = ( |
697 | @snmp_watcher = ( |
534 | (map { EV::io $_, EV::READ, sub { } } |
698 | (map { EV::io $_, EV::READ, sub { } } |
535 | keys %{ $dispatcher->{_descriptors} }), |
699 | keys %{ $dispatcher->{_descriptors} }), |
536 | |
700 | |
537 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
701 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
… | |
… | |
565 | is done before the event loop blocks next and before "check" watchers |
729 | is done before the event loop blocks next and before "check" watchers |
566 | are being called, and only in the child after the fork. |
730 | are being called, and only in the child after the fork. |
567 | |
731 | |
568 | $w = EV::fork $callback |
732 | $w = EV::fork $callback |
569 | $w = EV::fork_ns $callback |
733 | $w = EV::fork_ns $callback |
|
|
734 | $w = $loop->fork ($callback) |
|
|
735 | $w = $loop->fork_ns ($callback) |
570 | Call the callback before the event loop is resumed in the child |
736 | Call the callback before the event loop is resumed in the child |
571 | process after a fork. |
737 | process after a fork. |
572 | |
738 | |
573 | The "fork_ns" variant doesn't start (activate) the newly created |
739 | The "fork_ns" variant doesn't start (activate) the newly created |
574 | watcher. |
740 | watcher. |
|
|
741 | |
|
|
742 | EMBED WATCHERS - when one backend isn't enough... |
|
|
743 | This is a rather advanced watcher type that lets you embed one event |
|
|
744 | loop into another (currently only IO events are supported in the |
|
|
745 | embedded loop, other types of watchers might be handled in a delayed or |
|
|
746 | incorrect fashion and must not be used). |
|
|
747 | |
|
|
748 | See the libev documentation at |
|
|
749 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code |
|
|
750 | _when_one_backend_> for more details. |
|
|
751 | |
|
|
752 | In short, this watcher is most useful on BSD systems without working |
|
|
753 | kqueue to still be able to handle a large number of sockets: |
|
|
754 | |
|
|
755 | my $socket_loop; |
|
|
756 | |
|
|
757 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
758 | if ( |
|
|
759 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
760 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
761 | ) { |
|
|
762 | # use kqueue for sockets |
|
|
763 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
764 | } |
|
|
765 | |
|
|
766 | # use the default loop otherwise |
|
|
767 | $socket_loop ||= EV::default_loop; |
|
|
768 | |
|
|
769 | $w = EV::embed $otherloop, $callback |
|
|
770 | $w = EV::embed_ns $otherloop, $callback |
|
|
771 | $w = $loop->embed ($otherloop, $callback) |
|
|
772 | $w = $loop->embed_ns ($otherloop, $callback) |
|
|
773 | Call the callback when the embedded event loop ($otherloop) has any |
|
|
774 | I/O activity. The $callback should alwas be specified as "undef" in |
|
|
775 | this version of EV, which means the embedded event loop will be |
|
|
776 | managed automatically. |
|
|
777 | |
|
|
778 | The "embed_ns" variant doesn't start (activate) the newly created |
|
|
779 | watcher. |
|
|
780 | |
|
|
781 | PERL SIGNALS |
|
|
782 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
|
|
783 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
784 | handled when Perl runs, which means your signal handler might be invoked |
|
|
785 | only the next time an event callback is invoked. |
|
|
786 | |
|
|
787 | The solution is to use EV signal watchers (see "EV::signal"), which will |
|
|
788 | ensure proper operations with regards to other event watchers. |
|
|
789 | |
|
|
790 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
791 | to be called on every event loop iteration by installing a "EV::check" |
|
|
792 | watcher: |
|
|
793 | |
|
|
794 | my $async_check = EV::check sub { }; |
|
|
795 | |
|
|
796 | This ensures that perl gets into control for a short time to handle any |
|
|
797 | pending signals, and also ensures (slightly) slower overall operation. |
575 | |
798 | |
576 | THREADS |
799 | THREADS |
577 | Threads are not supported by this module in any way. Perl pseudo-threads |
800 | Threads are not supported by this module in any way. Perl pseudo-threads |
578 | is evil stuff and must die. As soon as Perl gains real threads I will |
801 | is evil stuff and must die. As soon as Perl gains real threads I will |
579 | work on thread support for it. |
802 | work on thread support for it. |
… | |
… | |
594 | |
817 | |
595 | On win32, there is no notion of fork so all this doesn't apply, of |
818 | On win32, there is no notion of fork so all this doesn't apply, of |
596 | course. |
819 | course. |
597 | |
820 | |
598 | SEE ALSO |
821 | SEE ALSO |
599 | EV::DNS. |
822 | EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event |
|
|
823 | loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines |
|
|
824 | with EV), Net::SNMP::EV (asynchronous SNMP). |
600 | |
825 | |
601 | AUTHOR |
826 | AUTHOR |
602 | Marc Lehmann <schmorp@schmorp.de> |
827 | Marc Lehmann <schmorp@schmorp.de> |
603 | http://home.schmorp.de/ |
828 | http://home.schmorp.de/ |
604 | |
829 | |