1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | EV - perl interface to libevent, monkey.org/~provos/libevent/ |
3 | EV - perl interface to libev, a high performance full-featured event loop |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use EV; |
7 | use EV; |
8 | |
8 | |
9 | # TIMER |
9 | # TIMERS |
10 | |
10 | |
11 | my $w = EV::timer 2, 0, sub { |
11 | my $w = EV::timer 2, 0, sub { |
12 | warn "is called after 2s"; |
12 | warn "is called after 2s"; |
13 | }; |
13 | }; |
14 | |
14 | |
15 | my $w = EV::timer 2, 1, sub { |
15 | my $w = EV::timer 2, 2, sub { |
16 | warn "is called roughly every 2s (repeat = 1)"; |
16 | warn "is called roughly every 2s (repeat = 2)"; |
17 | }; |
17 | }; |
18 | |
18 | |
19 | undef $w; # destroy event watcher again |
19 | undef $w; # destroy event watcher again |
20 | |
20 | |
21 | my $w = EV::timer_abs 0, 60, sub { |
21 | my $w = EV::periodic 0, 60, 0, sub { |
22 | warn "is called every minute, on the minute, exactly"; |
22 | warn "is called every minute, on the minute, exactly"; |
23 | }; |
23 | }; |
24 | |
24 | |
25 | # IO |
25 | # IO |
26 | |
26 | |
27 | my $w = EV::io \*STDIN, EV::READ | EV::PERSIST, sub { |
27 | my $w = EV::io *STDIN, EV::READ, sub { |
28 | my ($w, $revents) = @_; # all callbacks get the watcher object and event mask |
28 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
29 | if ($revents & EV::TIMEOUT) { |
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30 | warn "nothing received on stdin for 10 seconds, retrying"; |
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31 | } else { |
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32 | warn "stdin is readable, you entered: ", <STDIN>; |
29 | warn "stdin is readable, you entered: ", <STDIN>; |
33 | } |
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34 | }; |
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35 | $w->timeout (10); |
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36 | |
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37 | my $w = EV::timed_io \*STDIN, EV::READ, 30, sub { |
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38 | my ($w, $revents) = @_; |
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39 | if ($revents & EV::TIMEOUT) { |
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40 | warn "nothing entered within 30 seconds, bye bye.\n"; |
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41 | $w->stop; |
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42 | } else { |
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43 | my $line = <STDIN>; |
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44 | warn "you entered something, you again have 30 seconds.\n"; |
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45 | } |
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46 | }; |
30 | }; |
47 | |
31 | |
48 | # SIGNALS |
32 | # SIGNALS |
49 | |
33 | |
50 | my $w = EV::signal 'QUIT', sub { |
34 | my $w = EV::signal 'QUIT', sub { |
51 | warn "sigquit received\n"; |
35 | warn "sigquit received\n"; |
52 | }; |
36 | }; |
53 | |
37 | |
54 | my $w = EV::signal 3, sub { |
38 | # CHILD/PID STATUS CHANGES |
55 | warn "sigquit received (this is GNU/Linux, right?)\n"; |
39 | |
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40 | my $w = EV::child 666, 0, sub { |
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41 | my ($w, $revents) = @_; |
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42 | my $status = $w->rstatus; |
56 | }; |
43 | }; |
57 | |
44 | |
58 | # CHILD/PID STATUS CHANGES |
45 | # STAT CHANGES |
59 | |
46 | my $w = EV::stat "/etc/passwd", 10, sub { |
60 | my $w = EV::child 666, sub { |
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61 | my ($w, $revents, $status) = @_; |
47 | my ($w, $revents) = @_; |
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48 | warn $w->path, " has changed somehow.\n"; |
62 | }; |
49 | }; |
63 | |
50 | |
64 | # MAINLOOP |
51 | # MAINLOOP |
65 | EV::dispatch; # loop as long as watchers are active |
52 | EV::loop; # loop until EV::unloop is called or all watchers stop |
66 | EV::loop; # the same thing |
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67 | EV::loop EV::LOOP_ONESHOT; # block until some events could be handles |
53 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
68 | EV::loop EV::LOOP_NONBLOCK; # check and handle some events, but do not wait |
54 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
69 | |
55 | |
70 | =head1 DESCRIPTION |
56 | =head1 DESCRIPTION |
71 | |
57 | |
72 | This module provides an interface to libev |
58 | This module provides an interface to libev |
73 | (L<http://software.schmorp.de/pkg/libev.html>). You probably should |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
74 | acquaint yourself with its documentation and source code to be able to use |
60 | below is comprehensive, one might also consult the documentation of libev |
75 | this module fully. |
61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
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62 | watcher semantics or some discussion on the available backends, or how to |
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63 | force a specific backend with C<LIBEV_FLAGS>, or just about in any case |
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64 | because it has much more detailed information. |
76 | |
65 | |
77 | =cut |
66 | =cut |
78 | |
67 | |
79 | package EV; |
68 | package EV; |
80 | |
69 | |
81 | use strict; |
70 | use strict; |
82 | |
71 | |
83 | BEGIN { |
72 | BEGIN { |
84 | our $VERSION = '0.03'; |
73 | our $VERSION = '3.1'; |
85 | use XSLoader; |
74 | use XSLoader; |
86 | XSLoader::load "EV", $VERSION; |
75 | XSLoader::load "EV", $VERSION; |
87 | } |
76 | } |
88 | |
77 | |
89 | @EV::Io::ISA = "EV::Watcher"; |
78 | @EV::IO::ISA = |
90 | @EV::Time::ISA = "EV::Watcher"; |
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91 | @EV::Timer::ISA = "EV::Time"; |
79 | @EV::Timer::ISA = |
92 | @EV::Periodic::ISA = "EV::Time"; |
80 | @EV::Periodic::ISA = |
93 | @EV::Signal::ISA = "EV::Watcher"; |
81 | @EV::Signal::ISA = |
94 | @EV::Idle::ISA = "EV::Watcher"; |
82 | @EV::Child::ISA = |
95 | @EV::Prepare::ISA = "EV::Watcher"; |
83 | @EV::Stat::ISA = |
96 | @EV::Check::ISA = "EV::Watcher"; |
84 | @EV::Idle::ISA = |
97 | @EV::Child::ISA = "EV::Watcher"; |
85 | @EV::Prepare::ISA = |
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86 | @EV::Check::ISA = |
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87 | @EV::Embed::ISA = |
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88 | @EV::Fork::ISA = |
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89 | @EV::Async::ISA = |
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90 | "EV::Watcher"; |
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91 | |
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92 | @EV::Loop::Default::ISA = "EV::Loop"; |
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93 | |
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94 | =head1 EVENT LOOPS |
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95 | |
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96 | EV supports multiple event loops: There is a single "default event loop" |
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97 | that can handle everything including signals and child watchers, and any |
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98 | number of "dynamic event loops" that can use different backends (with |
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99 | various limitations), but no child and signal watchers. |
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100 | |
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101 | You do not have to do anything to create the default event loop: When |
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102 | the module is loaded a suitable backend is selected on the premise of |
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103 | selecting a working backend (which for example rules out kqueue on most |
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104 | BSDs). Modules should, unless they have "special needs" always use the |
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105 | default loop as this is fastest (perl-wise), best supported by other |
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106 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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107 | |
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108 | For specific programs you can create additional event loops dynamically. |
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109 | |
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110 | =over 4 |
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111 | |
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112 | =item $loop = new EV::loop [$flags] |
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113 | |
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114 | Create a new event loop as per the specified flags. Please refer to the |
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115 | C<ev_loop_new ()> function description in the libev documentation |
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116 | (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) |
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117 | for more info. |
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118 | |
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119 | The loop will automatically be destroyed when it is no longer referenced |
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120 | by any watcher and the loop object goes out of scope. |
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121 | |
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122 | Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop |
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123 | is protected by this module. |
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124 | |
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125 | =item $loop->loop_fork |
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126 | |
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127 | Must be called after a fork in the child, before entering or continuing |
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128 | the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls |
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129 | this fucntion automatically, at some performance loss (refer to the libev |
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130 | documentation). |
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131 | |
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132 | =item $loop = EV::default_loop [$flags] |
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133 | |
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134 | Return the default loop (which is a singleton object). |
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135 | |
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136 | =back |
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137 | |
98 | |
138 | |
99 | =head1 BASIC INTERFACE |
139 | =head1 BASIC INTERFACE |
100 | |
140 | |
101 | =over 4 |
141 | =over 4 |
102 | |
142 | |
103 | =item $EV::NPRI |
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104 | |
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105 | How many priority levels are available. |
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106 | |
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107 | =item $EV::DIED |
143 | =item $EV::DIED |
108 | |
144 | |
109 | Must contain a reference to a function that is called when a callback |
145 | Must contain a reference to a function that is called when a callback |
110 | throws an exception (with $@ containing thr error). The default prints an |
146 | throws an exception (with $@ containing the error). The default prints an |
111 | informative message and continues. |
147 | informative message and continues. |
112 | |
148 | |
113 | If this callback throws an exception it will be silently ignored. |
149 | If this callback throws an exception it will be silently ignored. |
114 | |
150 | |
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151 | =item $flags = EV::supported_backends |
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152 | |
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153 | =item $flags = EV::recommended_backends |
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154 | |
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155 | =item $flags = EV::embeddable_backends |
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156 | |
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157 | Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this |
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158 | instance of EV, the set of recommended backends (supposed to be good) for |
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159 | this platform and the set of embeddable backends (see EMBED WATCHERS). |
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160 | |
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161 | =item EV::sleep $seconds |
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162 | |
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163 | Block the process for the given number of (fractional) seconds. |
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164 | |
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165 | =item $time = EV::time |
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166 | |
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167 | Returns the current time in (fractional) seconds since the epoch. |
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168 | |
115 | =item $time = EV::now |
169 | =item $time = EV::now |
116 | |
170 | |
117 | Returns the time in (fractional) seconds since the epoch. |
171 | =item $time = $loop->now |
118 | |
172 | |
119 | =item $version = EV::version |
173 | Returns the time the last event loop iteration has been started. This |
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174 | is the time that (relative) timers are based on, and refering to it is |
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175 | usually faster then calling EV::time. |
120 | |
176 | |
121 | =item $method = EV::method |
177 | =item $backend = EV::backend |
122 | |
178 | |
123 | Return version string and event polling method used. |
179 | =item $backend = $loop->backend |
124 | |
180 | |
125 | =item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT |
181 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
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182 | or EV::METHOD_EPOLL). |
126 | |
183 | |
127 | =item EV::loopexit $after |
184 | =item EV::loop [$flags] |
128 | |
185 | |
129 | Exit any active loop or dispatch after C<$after> seconds or immediately if |
186 | =item $loop->loop ([$flags]) |
130 | C<$after> is missing or zero. |
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131 | |
187 | |
132 | =item EV::dispatch |
188 | Begin checking for events and calling callbacks. It returns when a |
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189 | callback calls EV::unloop. |
133 | |
190 | |
134 | Same as C<EV::loop 0>. |
191 | The $flags argument can be one of the following: |
135 | |
192 | |
136 | =item EV::event $callback |
193 | 0 as above |
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194 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
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195 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
137 | |
196 | |
138 | Creates a new event watcher waiting for nothing, calling the given callback. |
197 | =item EV::unloop [$how] |
139 | |
198 | |
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199 | =item $loop->unloop ([$how]) |
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200 | |
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201 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
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202 | innermost call to EV::loop return. |
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203 | |
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204 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
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205 | fast as possible. |
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206 | |
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207 | =item $count = EV::loop_count |
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208 | |
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209 | =item $count = $loop->loop_count |
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210 | |
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211 | Return the number of times the event loop has polled for new |
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212 | events. Sometiems useful as a generation counter. |
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213 | |
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214 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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215 | |
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216 | =item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
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217 | |
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218 | This function rolls together an I/O and a timer watcher for a single |
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219 | one-shot event without the need for managing a watcher object. |
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220 | |
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221 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
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222 | must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
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223 | | EV::WRITE>, indicating the type of I/O event you want to wait for. If |
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224 | you do not want to wait for some I/O event, specify C<undef> for |
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225 | C<$fh_or_undef> and C<0> for C<$events>). |
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226 | |
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227 | If timeout is C<undef> or negative, then there will be no |
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228 | timeout. Otherwise a EV::timer with this value will be started. |
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229 | |
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230 | When an error occurs or either the timeout or I/O watcher triggers, then |
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231 | the callback will be called with the received event set (in general |
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232 | you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, |
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233 | C<EV::WRITE> and C<EV::TIMEOUT>). |
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234 | |
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235 | EV::once doesn't return anything: the watchers stay active till either |
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236 | of them triggers, then they will be stopped and freed, and the callback |
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237 | invoked. |
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238 | |
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239 | =item EV::feed_fd_event ($fd, $revents) |
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240 | |
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241 | =item $loop->feed_fd_event ($fd, $revents) |
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242 | |
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243 | Feed an event on a file descriptor into EV. EV will react to this call as |
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244 | if the readyness notifications specified by C<$revents> (a combination of |
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245 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
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246 | |
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247 | =item EV::feed_signal_event ($signal) |
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248 | |
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249 | Feed a signal event into EV. EV will react to this call as if the signal |
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250 | specified by C<$signal> had occured. |
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251 | |
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252 | =item EV::set_io_collect_interval $time |
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253 | |
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254 | =item $loop->set_io_collect_interval ($time) |
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255 | |
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256 | =item EV::set_timeout_collect_interval $time |
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257 | |
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258 | =item $loop->set_timeout_collect_interval ($time) |
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259 | |
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260 | These advanced functions set the minimum block interval when polling for I/O events and the minimum |
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261 | wait interval for timer events. See the libev documentation at |
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262 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for |
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263 | a more detailed discussion. |
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264 | |
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265 | =back |
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266 | |
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267 | |
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268 | =head1 WATCHER OBJECTS |
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269 | |
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270 | A watcher is an object that gets created to record your interest in some |
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271 | event. For instance, if you want to wait for STDIN to become readable, you |
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272 | would create an EV::io watcher for that: |
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273 | |
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274 | my $watcher = EV::io *STDIN, EV::READ, sub { |
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275 | my ($watcher, $revents) = @_; |
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276 | warn "yeah, STDIN should now be readable without blocking!\n" |
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277 | }; |
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278 | |
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279 | All watchers can be active (waiting for events) or inactive (paused). Only |
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280 | active watchers will have their callbacks invoked. All callbacks will be |
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281 | called with at least two arguments: the watcher and a bitmask of received |
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282 | events. |
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283 | |
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284 | Each watcher type has its associated bit in revents, so you can use the |
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285 | same callback for multiple watchers. The event mask is named after the |
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286 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
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287 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
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288 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
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289 | uses EV::TIMEOUT). |
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290 | |
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291 | In the rare case where one wants to create a watcher but not start it at |
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292 | the same time, each constructor has a variant with a trailing C<_ns> in |
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293 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
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294 | |
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295 | Please note that a watcher will automatically be stopped when the watcher |
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296 | object is destroyed, so you I<need> to keep the watcher objects returned by |
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297 | the constructors. |
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298 | |
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299 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
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300 | ->fh and so on) automatically stop and start it again if it is active, |
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301 | which means pending events get lost. |
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302 | |
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303 | =head2 COMMON WATCHER METHODS |
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304 | |
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305 | This section lists methods common to all watchers. |
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306 | |
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307 | =over 4 |
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308 | |
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309 | =item $w->start |
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310 | |
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311 | Starts a watcher if it isn't active already. Does nothing to an already |
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312 | active watcher. By default, all watchers start out in the active state |
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313 | (see the description of the C<_ns> variants if you need stopped watchers). |
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314 | |
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315 | =item $w->stop |
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316 | |
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317 | Stop a watcher if it is active. Also clear any pending events (events that |
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318 | have been received but that didn't yet result in a callback invocation), |
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319 | regardless of whether the watcher was active or not. |
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320 | |
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321 | =item $bool = $w->is_active |
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322 | |
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323 | Returns true if the watcher is active, false otherwise. |
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324 | |
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325 | =item $current_data = $w->data |
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326 | |
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327 | =item $old_data = $w->data ($new_data) |
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328 | |
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329 | Queries a freely usable data scalar on the watcher and optionally changes |
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330 | it. This is a way to associate custom data with a watcher: |
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331 | |
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332 | my $w = EV::timer 60, 0, sub { |
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333 | warn $_[0]->data; |
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334 | }; |
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335 | $w->data ("print me!"); |
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336 | |
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337 | =item $current_cb = $w->cb |
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338 | |
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339 | =item $old_cb = $w->cb ($new_cb) |
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340 | |
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341 | Queries the callback on the watcher and optionally changes it. You can do |
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342 | this at any time without the watcher restarting. |
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343 | |
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344 | =item $current_priority = $w->priority |
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345 | |
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346 | =item $old_priority = $w->priority ($new_priority) |
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347 | |
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348 | Queries the priority on the watcher and optionally changes it. Pending |
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349 | watchers with higher priority will be invoked first. The valid range of |
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350 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
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351 | -2). If the priority is outside this range it will automatically be |
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352 | normalised to the nearest valid priority. |
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353 | |
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354 | The default priority of any newly-created watcher is 0. |
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355 | |
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356 | Note that the priority semantics have not yet been fleshed out and are |
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357 | subject to almost certain change. |
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358 | |
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359 | =item $w->invoke ($revents) |
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360 | |
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361 | Call the callback *now* with the given event mask. |
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362 | |
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363 | =item $w->feed_event ($revents) |
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364 | |
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365 | Feed some events on this watcher into EV. EV will react to this call as if |
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366 | the watcher had received the given C<$revents> mask. |
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367 | |
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368 | =item $revents = $w->clear_pending |
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369 | |
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370 | If the watcher is pending, this function clears its pending status and |
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371 | returns its C<$revents> bitset (as if its callback was invoked). If the |
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372 | watcher isn't pending it does nothing and returns C<0>. |
|
|
373 | |
|
|
374 | =item $previous_state = $w->keepalive ($bool) |
|
|
375 | |
|
|
376 | Normally, C<EV::loop> will return when there are no active watchers |
|
|
377 | (which is a "deadlock" because no progress can be made anymore). This is |
|
|
378 | convinient because it allows you to start your watchers (and your jobs), |
|
|
379 | call C<EV::loop> once and when it returns you know that all your jobs are |
|
|
380 | finished (or they forgot to register some watchers for their task :). |
|
|
381 | |
|
|
382 | Sometimes, however, this gets in your way, for example when the module |
|
|
383 | that calls C<EV::loop> (usually the main program) is not the same module |
|
|
384 | as a long-living watcher (for example a DNS client module written by |
|
|
385 | somebody else even). Then you might want any outstanding requests to be |
|
|
386 | handled, but you would not want to keep C<EV::loop> from returning just |
|
|
387 | because you happen to have this long-running UDP port watcher. |
|
|
388 | |
|
|
389 | In this case you can clear the keepalive status, which means that even |
|
|
390 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
|
391 | |
|
|
392 | The initial value for keepalive is true (enabled), and you cna change it |
|
|
393 | any time. |
|
|
394 | |
|
|
395 | Example: Register an I/O watcher for some UDP socket but do not keep the |
|
|
396 | event loop from running just because of that watcher. |
|
|
397 | |
|
|
398 | my $udp_socket = ... |
|
|
399 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
400 | $1000udp_watcher->keepalive (0); |
|
|
401 | |
|
|
402 | =item $loop = $w->loop |
|
|
403 | |
|
|
404 | Return the loop that this watcher is attached to. |
|
|
405 | |
|
|
406 | =back |
|
|
407 | |
|
|
408 | |
|
|
409 | =head1 WATCHER TYPES |
|
|
410 | |
|
|
411 | Each of the following subsections describes a single watcher type. |
|
|
412 | |
|
|
413 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
|
414 | |
|
|
415 | =over 4 |
|
|
416 | |
140 | =item my $w = EV::io $fileno_or_fh, $eventmask, $callback |
417 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
141 | |
418 | |
142 | =item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
419 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
|
|
420 | |
|
|
421 | =item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
422 | |
|
|
423 | =item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
143 | |
424 | |
144 | As long as the returned watcher object is alive, call the C<$callback> |
425 | As long as the returned watcher object is alive, call the C<$callback> |
145 | when the events specified in C<$eventmask> happen. Initially, the timeout |
426 | when at least one of events specified in C<$eventmask> occurs. |
146 | is disabled. |
|
|
147 | |
427 | |
148 | You can additionall set a timeout to occur on the watcher, but note that |
|
|
149 | this timeout will not be reset when you get an I/O event in the EV::PERSIST |
|
|
150 | case, and reaching a timeout will always stop the watcher even in the |
|
|
151 | EV::PERSIST case. |
|
|
152 | |
|
|
153 | If you want a timeout to occur only after a specific time of inactivity, set |
|
|
154 | a repeating timeout and do NOT use EV::PERSIST. |
|
|
155 | |
|
|
156 | Eventmask can be one or more of these constants ORed together: |
428 | The $eventmask can be one or more of these constants ORed together: |
157 | |
429 | |
158 | EV::READ wait until read() wouldn't block anymore |
430 | EV::READ wait until read() wouldn't block anymore |
159 | EV::WRITE wait until write() wouldn't block anymore |
431 | EV::WRITE wait until write() wouldn't block anymore |
160 | EV::PERSIST stay active after a (non-timeout) event occured |
|
|
161 | |
432 | |
162 | The C<io_ns> variant doesn't add/start the newly created watcher. |
433 | The C<io_ns> variant doesn't start (activate) the newly created watcher. |
163 | |
434 | |
164 | =item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback |
435 | =item $w->set ($fileno_or_fh, $eventmask) |
165 | |
436 | |
166 | =item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback |
437 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
438 | called at any time. |
167 | |
439 | |
168 | Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was |
440 | =item $current_fh = $w->fh |
169 | a call to C<< $w->timeout ($timout, 1) >>. The persist flag is not allowed |
|
|
170 | and will automatically be cleared. The watcher will be restarted after each event. |
|
|
171 | |
441 | |
172 | If the timeout is zero or undef, no timeout will be set, and a normal |
442 | =item $old_fh = $w->fh ($new_fh) |
173 | watcher (with the persist flag set!) will be created. |
|
|
174 | |
443 | |
175 | This has the effect of timing out after the specified period of inactivity |
444 | Returns the previously set filehandle and optionally set a new one. |
176 | has happened. |
|
|
177 | |
445 | |
178 | Due to the design of libevent, this is also relatively inefficient, having |
446 | =item $current_eventmask = $w->events |
179 | one or two io watchers and a separate timeout watcher that you reset on |
|
|
180 | activity (by calling its C<start> method) is usually more efficient. |
|
|
181 | |
447 | |
|
|
448 | =item $old_eventmask = $w->events ($new_eventmask) |
|
|
449 | |
|
|
450 | Returns the previously set event mask and optionally set a new one. |
|
|
451 | |
|
|
452 | =back |
|
|
453 | |
|
|
454 | |
|
|
455 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
|
456 | |
|
|
457 | =over 4 |
|
|
458 | |
182 | =item my $w = EV::timer $after, $repeat, $callback |
459 | =item $w = EV::timer $after, $repeat, $callback |
183 | |
460 | |
184 | =item my $w = EV::timer_ns $after, $repeat, $callback |
461 | =item $w = EV::timer_ns $after, $repeat, $callback |
185 | |
462 | |
186 | Calls the callback after C<$after> seconds. If C<$repeat> is true, the |
463 | =item $w = $loop->timer ($after, $repeat, $callback) |
187 | timer will be restarted after the callback returns. This means that the |
|
|
188 | callback would be called roughly every C<$after> seconds, prolonged by the |
|
|
189 | time the callback takes. |
|
|
190 | |
464 | |
|
|
465 | =item $w = $loop->timer_ns ($after, $repeat, $callback) |
|
|
466 | |
|
|
467 | Calls the callback after C<$after> seconds (which may be fractional). If |
|
|
468 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
|
|
469 | value as $after) after the callback returns. |
|
|
470 | |
|
|
471 | This means that the callback would be called roughly after C<$after> |
|
|
472 | seconds, and then every C<$repeat> seconds. The timer does his best not |
|
|
473 | to drift, but it will not invoke the timer more often then once per event |
|
|
474 | loop iteration, and might drift in other cases. If that isn't acceptable, |
|
|
475 | look at EV::periodic, which can provide long-term stable timers. |
|
|
476 | |
|
|
477 | The timer is based on a monotonic clock, that is, if somebody is sitting |
|
|
478 | in front of the machine while the timer is running and changes the system |
|
|
479 | clock, the timer will nevertheless run (roughly) the same time. |
|
|
480 | |
191 | The C<timer_ns> variant doesn't add/start the newly created watcher. |
481 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
192 | |
482 | |
193 | =item my $w = EV::timer_abs $at, $interval, $callback |
483 | =item $w->set ($after, $repeat) |
194 | |
484 | |
195 | =item my $w = EV::timer_abs_ns $at, $interval, $callback |
485 | Reconfigures the watcher, see the constructor above for details. Can be called at |
|
|
486 | any time. |
196 | |
487 | |
197 | Similar to EV::timer, but the time is given as an absolute point in time |
488 | =item $w->again |
198 | (C<$at>), plus an optional C<$interval>. |
|
|
199 | |
489 | |
200 | If the C<$interval> is zero, then the callback will be called at the time |
490 | Similar to the C<start> method, but has special semantics for repeating timers: |
201 | C<$at> if that is in the future, or as soon as possible if its in the |
|
|
202 | past. It will not automatically repeat. |
|
|
203 | |
491 | |
204 | If the C<$interval> is nonzero, then the watcher will always be scheduled |
492 | If the timer is active and non-repeating, it will be stopped. |
205 | to time out at the next C<$at + integer * $interval> time. |
|
|
206 | |
493 | |
207 | This can be used to schedule a callback to run at very regular intervals, |
494 | If the timer is active and repeating, reset the timeout to occur |
208 | as long as the processing time is less then the interval (otherwise |
495 | C<$repeat> seconds after now. |
209 | obviously events will be skipped). |
496 | |
|
|
497 | If the timer is inactive and repeating, start it using the repeat value. |
|
|
498 | |
|
|
499 | Otherwise do nothing. |
|
|
500 | |
|
|
501 | This behaviour is useful when you have a timeout for some IO |
|
|
502 | operation. You create a timer object with the same value for C<$after> and |
|
|
503 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
|
|
504 | on the timeout. |
|
|
505 | |
|
|
506 | =back |
|
|
507 | |
|
|
508 | |
|
|
509 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
510 | |
|
|
511 | =over 4 |
|
|
512 | |
|
|
513 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
|
|
514 | |
|
|
515 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
|
|
516 | |
|
|
517 | =item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
|
|
518 | |
|
|
519 | =item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
|
|
520 | |
|
|
521 | Similar to EV::timer, but is not based on relative timeouts but on |
|
|
522 | absolute times. Apart from creating "simple" timers that trigger "at" the |
|
|
523 | specified time, it can also be used for non-drifting absolute timers and |
|
|
524 | more complex, cron-like, setups that are not adversely affected by time |
|
|
525 | jumps (i.e. when the system clock is changed by explicit date -s or other |
|
|
526 | means such as ntpd). It is also the most complex watcher type in EV. |
|
|
527 | |
|
|
528 | It has three distinct "modes": |
|
|
529 | |
|
|
530 | =over 4 |
|
|
531 | |
|
|
532 | =item * absolute timer ($interval = $reschedule_cb = 0) |
|
|
533 | |
|
|
534 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
|
|
535 | will not adjust when a time jump occurs, that is, if it is to be run |
|
|
536 | at January 1st 2011 then it will run when the system time reaches or |
|
|
537 | surpasses this time. |
|
|
538 | |
|
|
539 | =item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
540 | |
|
|
541 | In this mode the watcher will always be scheduled to time out at the |
|
|
542 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
|
|
543 | regardless of any time jumps. |
|
|
544 | |
|
|
545 | This can be used to create timers that do not drift with respect to system |
|
|
546 | time: |
|
|
547 | |
|
|
548 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
|
549 | |
|
|
550 | That doesn't mean there will always be 3600 seconds in between triggers, |
|
|
551 | but only that the the clalback will be called when the system time shows a |
|
|
552 | full hour (UTC). |
210 | |
553 | |
211 | Another way to think about it (for the mathematically inclined) is that |
554 | Another way to think about it (for the mathematically inclined) is that |
212 | C<timer_abs> will try to tun the callback at the next possible time where |
555 | EV::periodic will try to run the callback in this mode at the next |
213 | C<$time = $at (mod $interval)>, regardless of any time jumps. |
556 | possible time where C<$time = $at (mod $interval)>, regardless of any time |
|
|
557 | jumps. |
214 | |
558 | |
|
|
559 | =item * manual reschedule mode ($reschedule_cb = coderef) |
|
|
560 | |
|
|
561 | In this mode $interval and $at are both being ignored. Instead, each |
|
|
562 | time the periodic watcher gets scheduled, the reschedule callback |
|
|
563 | ($reschedule_cb) will be called with the watcher as first, and the current |
|
|
564 | time as second argument. |
|
|
565 | |
|
|
566 | I<This callback MUST NOT stop or destroy this or any other periodic |
|
|
567 | watcher, ever>. If you need to stop it, return 1e30 and stop it |
|
|
568 | afterwards. |
|
|
569 | |
|
|
570 | It must return the next time to trigger, based on the passed time value |
|
|
571 | (that is, the lowest time value larger than to the second argument). It |
|
|
572 | will usually be called just before the callback will be triggered, but |
|
|
573 | might be called at other times, too. |
|
|
574 | |
|
|
575 | This can be used to create very complex timers, such as a timer that |
|
|
576 | triggers on each midnight, local time (actually 24 hours after the last |
|
|
577 | midnight, to keep the example simple. If you know a way to do it correctly |
|
|
578 | in about the same space (without requiring elaborate modules), drop me a |
|
|
579 | note :): |
|
|
580 | |
|
|
581 | my $daily = EV::periodic 0, 0, sub { |
|
|
582 | my ($w, $now) = @_; |
|
|
583 | |
|
|
584 | use Time::Local (); |
|
|
585 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
|
586 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
|
587 | }, sub { |
|
|
588 | print "it's midnight or likely shortly after, now\n"; |
|
|
589 | }; |
|
|
590 | |
|
|
591 | =back |
|
|
592 | |
215 | The C<timer_abs_ns> variant doesn't add/start the newly created watcher. |
593 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
216 | |
594 | |
|
|
595 | =item $w->set ($at, $interval, $reschedule_cb) |
|
|
596 | |
|
|
597 | Reconfigures the watcher, see the constructor above for details. Can be called at |
|
|
598 | any time. |
|
|
599 | |
|
|
600 | =item $w->again |
|
|
601 | |
|
|
602 | Simply stops and starts the watcher again. |
|
|
603 | |
|
|
604 | =item $time = $w->at |
|
|
605 | |
|
|
606 | Return the time that the watcher is expected to trigger next. |
|
|
607 | |
|
|
608 | =back |
|
|
609 | |
|
|
610 | |
|
|
611 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
612 | |
|
|
613 | =over 4 |
|
|
614 | |
217 | =item my $w = EV::signal $signal, $callback |
615 | =item $w = EV::signal $signal, $callback |
218 | |
616 | |
219 | =item my $w = EV::signal_ns $signal, $callback |
617 | =item $w = EV::signal_ns $signal, $callback |
220 | |
618 | |
221 | Call the callback when $signal is received (the signal can be specified |
619 | Call the callback when $signal is received (the signal can be specified by |
222 | by number or by name, just as with kill or %SIG). Signal watchers are |
620 | number or by name, just as with C<kill> or C<%SIG>). |
223 | persistent no natter what. |
|
|
224 | |
621 | |
225 | EV will grab the signal for the process (the kernel only allows one |
622 | EV will grab the signal for the process (the kernel only allows one |
226 | component to receive signals) when you start a signal watcher, and |
623 | component to receive a signal at a time) when you start a signal watcher, |
227 | removes it again when you stop it. Pelr does the same when you add/remove |
624 | and removes it again when you stop it. Perl does the same when you |
228 | callbacks to %SIG, so watch out. |
625 | add/remove callbacks to C<%SIG>, so watch out. |
229 | |
626 | |
230 | Unfortunately, only one handler can be registered per signal. Screw |
627 | You can have as many signal watchers per signal as you want. |
231 | libevent. |
|
|
232 | |
628 | |
233 | The C<signal_ns> variant doesn't add/start the newly created watcher. |
629 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
234 | |
630 | |
235 | =back |
631 | =item $w->set ($signal) |
236 | |
632 | |
237 | =head1 THE EV::Event CLASS |
633 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
634 | called at any time. |
238 | |
635 | |
239 | All EV functions creating an event watcher (designated by C<my $w => |
|
|
240 | above) support the following methods on the returned watcher object: |
|
|
241 | |
|
|
242 | =over 4 |
|
|
243 | |
|
|
244 | =item $w->add ($timeout) |
|
|
245 | |
|
|
246 | Stops and (re-)starts the event watcher, setting the optional timeout to |
|
|
247 | the given value, or clearing the timeout if none is given. |
|
|
248 | |
|
|
249 | =item $w->start |
|
|
250 | |
|
|
251 | Stops and (re-)starts the event watcher without touching the timeout. |
|
|
252 | |
|
|
253 | =item $w->del |
|
|
254 | |
|
|
255 | =item $w->stop |
|
|
256 | |
|
|
257 | Stop the event watcher if it was started. |
|
|
258 | |
|
|
259 | =item $current_callback = $w->cb |
|
|
260 | |
|
|
261 | =item $old_callback = $w->cb ($new_callback) |
|
|
262 | |
|
|
263 | Return the previously set callback and optionally set a new one. |
|
|
264 | |
|
|
265 | =item $current_fh = $w->fh |
|
|
266 | |
|
|
267 | =item $old_fh = $w->fh ($new_fh) |
|
|
268 | |
|
|
269 | Returns the previously set filehandle and optionally set a new one (also |
|
|
270 | clears the EV::SIGNAL flag when setting a filehandle). |
|
|
271 | |
|
|
272 | =item $current_signal = $w->signal |
636 | =item $current_signum = $w->signal |
273 | |
637 | |
274 | =item $old_signal = $w->signal ($new_signal) |
638 | =item $old_signum = $w->signal ($new_signal) |
275 | |
639 | |
|
|
640 | Returns the previously set signal (always as a number not name) and |
|
|
641 | optionally set a new one. |
|
|
642 | |
|
|
643 | =back |
|
|
644 | |
|
|
645 | |
|
|
646 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
647 | |
|
|
648 | =over 4 |
|
|
649 | |
|
|
650 | =item $w = EV::child $pid, $trace, $callback |
|
|
651 | |
|
|
652 | =item $w = EV::child_ns $pid, $trace, $callback |
|
|
653 | |
|
|
654 | =item $w = $loop->child ($pid, $trace, $callback) |
|
|
655 | |
|
|
656 | =item $w = $loop->child_ns ($pid, $trace, $callback) |
|
|
657 | |
|
|
658 | Call the callback when a status change for pid C<$pid> (or any pid |
|
|
659 | if C<$pid> is 0) has been received (a status change happens when the |
|
|
660 | process terminates or is killed, or, when trace is true, additionally when |
|
|
661 | it is stopped or continued). More precisely: when the process receives |
|
|
662 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
|
|
663 | changed/zombie children and call the callback. |
|
|
664 | |
|
|
665 | It is valid (and fully supported) to install a child watcher after a child |
|
|
666 | has exited but before the event loop has started its next iteration (for |
|
|
667 | example, first you C<fork>, then the new child process might exit, and |
|
|
668 | only then do you install a child watcher in the parent for the new pid). |
|
|
669 | |
|
|
670 | You can access both exit (or tracing) status and pid by using the |
|
|
671 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
672 | |
|
|
673 | You can have as many pid watchers per pid as you want, they will all be |
|
|
674 | called. |
|
|
675 | |
|
|
676 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
|
|
677 | |
|
|
678 | =item $w->set ($pid, $trace) |
|
|
679 | |
|
|
680 | Reconfigures the watcher, see the constructor above for details. Can be called at |
|
|
681 | any time. |
|
|
682 | |
|
|
683 | =item $current_pid = $w->pid |
|
|
684 | |
276 | Returns the previously set signal number and optionally set a new one (also sets |
685 | Returns the previously set process id and optionally set a new one. |
277 | the EV::SIGNAL flag when setting a signal). |
|
|
278 | |
686 | |
279 | =item $current_eventmask = $w->events |
687 | =item $exit_status = $w->rstatus |
280 | |
688 | |
281 | =item $old_eventmask = $w->events ($new_eventmask) |
689 | Return the exit/wait status (as returned by waitpid, see the waitpid entry |
|
|
690 | in perlfunc). |
282 | |
691 | |
|
|
692 | =item $pid = $w->rpid |
|
|
693 | |
|
|
694 | Return the pid of the awaited child (useful when you have installed a |
|
|
695 | watcher for all pids). |
|
|
696 | |
|
|
697 | =back |
|
|
698 | |
|
|
699 | |
|
|
700 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
701 | |
|
|
702 | =over 4 |
|
|
703 | |
|
|
704 | =item $w = EV::stat $path, $interval, $callback |
|
|
705 | |
|
|
706 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
707 | |
|
|
708 | =item $w = $loop->stat ($path, $interval, $callback) |
|
|
709 | |
|
|
710 | =item $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
711 | |
|
|
712 | Call the callback when a file status change has been detected on |
|
|
713 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
714 | to "path does not exist" is a status change like any other. |
|
|
715 | |
|
|
716 | The C<$interval> is a recommended polling interval for systems where |
|
|
717 | OS-supported change notifications don't exist or are not supported. If |
|
|
718 | you use C<0> then an unspecified default is used (which is highly |
|
|
719 | recommended!), which is to be expected to be around five seconds usually. |
|
|
720 | |
|
|
721 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
722 | as even with OS-supported change notifications, this can be |
|
|
723 | resource-intensive. |
|
|
724 | |
|
|
725 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
726 | |
|
|
727 | =item ... = $w->stat |
|
|
728 | |
|
|
729 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
730 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
731 | well as EV's idea of the current stat values) to the values found. |
|
|
732 | |
|
|
733 | In scalar context, a boolean is return indicating success or failure of |
|
|
734 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
735 | (except that the blksize and blocks fields are not reliable). |
|
|
736 | |
|
|
737 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
738 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
739 | was successful then nlink is guaranteed to be non-zero). |
|
|
740 | |
|
|
741 | See also the next two entries for more info. |
|
|
742 | |
|
|
743 | =item ... = $w->attr |
|
|
744 | |
|
|
745 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
746 | the values most recently detected by EV. See the next entry for more info. |
|
|
747 | |
|
|
748 | =item ... = $w->prev |
|
|
749 | |
|
|
750 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
751 | the previous set of values, before the change. |
|
|
752 | |
|
|
753 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
754 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
755 | returns the values found leading to the change detection. The difference (if any) |
|
|
756 | between C<prev> and C<attr> is what triggered the callback. |
|
|
757 | |
|
|
758 | If you did something to the filesystem object and do not want to trigger |
|
|
759 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
760 | current attributes are. |
|
|
761 | |
|
|
762 | =item $w->set ($path, $interval) |
|
|
763 | |
|
|
764 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
765 | called at any time. |
|
|
766 | |
|
|
767 | =item $current_path = $w->path |
|
|
768 | |
|
|
769 | =item $old_path = $w->path ($new_path) |
|
|
770 | |
283 | Returns the previously set event mask and optionally set a new one. |
771 | Returns the previously set path and optionally set a new one. |
284 | |
772 | |
285 | =item $w->timeout ($after, $repeat) |
773 | =item $current_interval = $w->interval |
286 | |
774 | |
287 | Resets the timeout (see C<EV::timer> for details). |
775 | =item $old_interval = $w->interval ($new_interval) |
288 | |
776 | |
289 | =item $w->timeout_abs ($at, $interval) |
777 | Returns the previously set interval and optionally set a new one. Can be |
|
|
778 | used to query the actual interval used. |
290 | |
779 | |
291 | Resets the timeout (see C<EV::timer_abs> for details). |
|
|
292 | |
|
|
293 | =item $w->priority_set ($priority) |
|
|
294 | |
|
|
295 | Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI). |
|
|
296 | |
|
|
297 | =back |
780 | =back |
|
|
781 | |
|
|
782 | |
|
|
783 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
784 | |
|
|
785 | =over 4 |
|
|
786 | |
|
|
787 | =item $w = EV::idle $callback |
|
|
788 | |
|
|
789 | =item $w = EV::idle_ns $callback |
|
|
790 | |
|
|
791 | =item $w = $loop->idle ($callback) |
|
|
792 | |
|
|
793 | =item $w = $loop->idle_ns ($callback) |
|
|
794 | |
|
|
795 | Call the callback when there are no other pending watchers of the same or |
|
|
796 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
797 | same or lower priority, of course). They are called idle watchers because |
|
|
798 | when the watcher is the highest priority pending event in the process, the |
|
|
799 | process is considered to be idle at that priority. |
|
|
800 | |
|
|
801 | If you want a watcher that is only ever called when I<no> other events are |
|
|
802 | outstanding you have to set the priority to C<EV::MINPRI>. |
|
|
803 | |
|
|
804 | The process will not block as long as any idle watchers are active, and |
|
|
805 | they will be called repeatedly until stopped. |
|
|
806 | |
|
|
807 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
808 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
809 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
810 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
811 | pending with the C<0>-priority idle watcher be invoked. |
|
|
812 | |
|
|
813 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
|
|
814 | |
|
|
815 | =back |
|
|
816 | |
|
|
817 | |
|
|
818 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
819 | |
|
|
820 | =over 4 |
|
|
821 | |
|
|
822 | =item $w = EV::prepare $callback |
|
|
823 | |
|
|
824 | =item $w = EV::prepare_ns $callback |
|
|
825 | |
|
|
826 | =item $w = $loop->prepare ($callback) |
|
|
827 | |
|
|
828 | =item $w = $loop->prepare_ns ($callback) |
|
|
829 | |
|
|
830 | Call the callback just before the process would block. You can still |
|
|
831 | create/modify any watchers at this point. |
|
|
832 | |
|
|
833 | See the EV::check watcher, below, for explanations and an example. |
|
|
834 | |
|
|
835 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
|
|
836 | |
|
|
837 | =back |
|
|
838 | |
|
|
839 | |
|
|
840 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
841 | |
|
|
842 | =over 4 |
|
|
843 | |
|
|
844 | =item $w = EV::check $callback |
|
|
845 | |
|
|
846 | =item $w = EV::check_ns $callback |
|
|
847 | |
|
|
848 | =item $w = $loop->check ($callback) |
|
|
849 | |
|
|
850 | =item $w = $loop->check_ns ($callback) |
|
|
851 | |
|
|
852 | Call the callback just after the process wakes up again (after it has |
|
|
853 | gathered events), but before any other callbacks have been invoked. |
|
|
854 | |
|
|
855 | This is used to integrate other event-based software into the EV |
|
|
856 | mainloop: You register a prepare callback and in there, you create io and |
|
|
857 | timer watchers as required by the other software. Here is a real-world |
|
|
858 | example of integrating Net::SNMP (with some details left out): |
|
|
859 | |
|
|
860 | our @snmp_watcher; |
|
|
861 | |
|
|
862 | our $snmp_prepare = EV::prepare sub { |
|
|
863 | # do nothing unless active |
|
|
864 | $dispatcher->{_event_queue_h} |
|
|
865 | or return; |
|
|
866 | |
|
|
867 | # make the dispatcher handle any outstanding stuff |
|
|
868 | ... not shown |
|
|
869 | |
|
|
870 | # create an I/O watcher for each and every socket |
|
|
871 | @snmp_watcher = ( |
|
|
872 | (map { EV::io $_, EV::READ, sub { } } |
|
|
873 | keys %{ $dispatcher->{_descriptors} }), |
|
|
874 | |
|
|
875 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
876 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
877 | 0, sub { }, |
|
|
878 | ); |
|
|
879 | }; |
|
|
880 | |
|
|
881 | The callbacks are irrelevant (and are not even being called), the |
|
|
882 | only purpose of those watchers is to wake up the process as soon as |
|
|
883 | one of those events occurs (socket readable, or timer timed out). The |
|
|
884 | corresponding EV::check watcher will then clean up: |
|
|
885 | |
|
|
886 | our $snmp_check = EV::check sub { |
|
|
887 | # destroy all watchers |
|
|
888 | @snmp_watcher = (); |
|
|
889 | |
|
|
890 | # make the dispatcher handle any new stuff |
|
|
891 | ... not shown |
|
|
892 | }; |
|
|
893 | |
|
|
894 | The callbacks of the created watchers will not be called as the watchers |
|
|
895 | are destroyed before this cna happen (remember EV::check gets called |
|
|
896 | first). |
|
|
897 | |
|
|
898 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
|
|
899 | |
|
|
900 | =back |
|
|
901 | |
|
|
902 | |
|
|
903 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
904 | |
|
|
905 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
906 | is done before the event loop blocks next and before C<check> watchers |
|
|
907 | are being called, and only in the child after the fork. |
|
|
908 | |
|
|
909 | =over 4 |
|
|
910 | |
|
|
911 | =item $w = EV::fork $callback |
|
|
912 | |
|
|
913 | =item $w = EV::fork_ns $callback |
|
|
914 | |
|
|
915 | =item $w = $loop->fork ($callback) |
|
|
916 | |
|
|
917 | =item $w = $loop->fork_ns ($callback) |
|
|
918 | |
|
|
919 | Call the callback before the event loop is resumed in the child process |
|
|
920 | after a fork. |
|
|
921 | |
|
|
922 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
923 | |
|
|
924 | =back |
|
|
925 | |
|
|
926 | |
|
|
927 | =head3 EMBED WATCHERS - when one backend isn't enough... |
|
|
928 | |
|
|
929 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
930 | into another (currently only IO events are supported in the embedded |
|
|
931 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
932 | fashion and must not be used). |
|
|
933 | |
|
|
934 | See the libev documentation at |
|
|
935 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> |
|
|
936 | for more details. |
|
|
937 | |
|
|
938 | In short, this watcher is most useful on BSD systems without working |
|
|
939 | kqueue to still be able to handle a large number of sockets: |
|
|
940 | |
|
|
941 | my $socket_loop; |
|
|
942 | |
|
|
943 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
944 | if ( |
|
|
945 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
946 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
947 | ) { |
|
|
948 | # use kqueue for sockets |
|
|
949 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
950 | } |
|
|
951 | |
|
|
952 | # use the default loop otherwise |
|
|
953 | $socket_loop ||= EV::default_loop; |
|
|
954 | |
|
|
955 | =over 4 |
|
|
956 | |
|
|
957 | =item $w = EV::embed $otherloop, $callback |
|
|
958 | |
|
|
959 | =item $w = EV::embed_ns $otherloop, $callback |
|
|
960 | |
|
|
961 | =item $w = $loop->embed ($otherloop, $callback) |
|
|
962 | |
|
|
963 | =item $w = $loop->embed_ns ($otherloop, $callback) |
|
|
964 | |
|
|
965 | Call the callback when the embedded event loop (C<$otherloop>) has any |
|
|
966 | I/O activity. The C<$callback> should alwas be specified as C<undef> in |
|
|
967 | this version of EV, which means the embedded event loop will be managed |
|
|
968 | automatically. |
|
|
969 | |
|
|
970 | The C<embed_ns> variant doesn't start (activate) the newly created watcher. |
|
|
971 | |
|
|
972 | =back |
|
|
973 | |
|
|
974 | =head3 ASYNC WATCHERS - how to wake up another event loop |
|
|
975 | |
|
|
976 | Async watchers are provided by EV, but have little use in perl directly, as perl |
|
|
977 | neither supports threads nor direct access to signal handlers or other |
|
|
978 | contexts where they could be of value. |
|
|
979 | |
|
|
980 | It is, however, possible to use them from the XS level. |
|
|
981 | |
|
|
982 | Please see the libev documentation for further details. |
|
|
983 | |
|
|
984 | |
|
|
985 | =head1 PERL SIGNALS |
|
|
986 | |
|
|
987 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
988 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
989 | handled when Perl runs, which means your signal handler might be invoked |
|
|
990 | only the next time an event callback is invoked. |
|
|
991 | |
|
|
992 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
993 | ensure proper operations with regards to other event watchers. |
|
|
994 | |
|
|
995 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
996 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
997 | watcher: |
|
|
998 | |
|
|
999 | my $async_check = EV::check sub { }; |
|
|
1000 | |
|
|
1001 | This ensures that perl gets into control for a short time to handle any |
|
|
1002 | pending signals, and also ensures (slightly) slower overall operation. |
298 | |
1003 | |
299 | =head1 THREADS |
1004 | =head1 THREADS |
300 | |
1005 | |
301 | Threads are not supported by this in any way. Perl pseudo-threads is evil |
1006 | Threads are not supported by this module in any way. Perl pseudo-threads |
302 | and must die. |
1007 | is evil stuff and must die. As soon as Perl gains real threads I will work |
|
|
1008 | on thread support for it. |
303 | |
1009 | |
304 | =head1 BUGS |
1010 | =head1 FORK |
305 | |
1011 | |
306 | Lots. Libevent itself isn't well tested and rather buggy, and this module |
1012 | Most of the "improved" event delivering mechanisms of modern operating |
307 | is quite new at the moment. |
1013 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
1014 | not supported and usually destructive). Libev makes it possible to work |
|
|
1015 | around this by having a function that recreates the kernel state after |
|
|
1016 | fork in the child. |
308 | |
1017 | |
309 | Please note that the epoll method is not, in general, reliable in programs |
1018 | On non-win32 platforms, this module requires the pthread_atfork |
310 | that use fork (even if no libveent calls are being made in the forked |
1019 | functionality to do this automatically for you. This function is quite |
311 | process). If your program behaves erratically, try setting the environment |
1020 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
312 | variable C<EVENT_NOEPOLL> first when running the program. |
1021 | negligible, because everything the function currently does is set a flag |
|
|
1022 | that is checked only when the event loop gets used the next time, so when |
|
|
1023 | you do fork but not use EV, the overhead is minimal. |
313 | |
1024 | |
314 | In general, if you fork, then you can only use the EV module in one of the |
1025 | On win32, there is no notion of fork so all this doesn't apply, of course. |
315 | children. |
|
|
316 | |
1026 | |
317 | =cut |
1027 | =cut |
318 | |
1028 | |
319 | our $DIED = sub { |
1029 | our $DIED = sub { |
320 | warn "EV: error in callback (ignoring): $@"; |
1030 | warn "EV: error in callback (ignoring): $@"; |
321 | }; |
1031 | }; |
322 | |
1032 | |
323 | init; |
1033 | default_loop |
324 | |
1034 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
325 | push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"]; |
|
|
326 | |
1035 | |
327 | 1; |
1036 | 1; |
328 | |
1037 | |
329 | =head1 SEE ALSO |
1038 | =head1 SEE ALSO |
330 | |
1039 | |
331 | L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>. |
1040 | L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as |
332 | L<EV::AnyEvent>. |
1041 | event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient |
|
|
1042 | coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP). |
333 | |
1043 | |
334 | =head1 AUTHOR |
1044 | =head1 AUTHOR |
335 | |
1045 | |
336 | Marc Lehmann <schmorp@schmorp.de> |
1046 | Marc Lehmann <schmorp@schmorp.de> |
337 | http://home.schmorp.de/ |
1047 | http://home.schmorp.de/ |