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 | # IO |
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22 | |
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23 | my $w = EV::timer_abs 0, 60, sub { |
21 | my $w = EV::periodic 0, 60, 0, sub { |
24 | warn "is called every minute, on the minute, exactly"; |
22 | warn "is called every minute, on the minute, exactly"; |
25 | }; |
23 | }; |
26 | |
24 | |
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25 | # IO |
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26 | |
27 | my $w = EV::io \*STDIN, EV::READ | EV::PERSIST, sub { |
27 | my $w = EV::io *STDIN, EV::READ, sub { |
28 | my ($w, $events) = @_; # all callbacks get the watcher object and event mask |
28 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
29 | if ($events & EV::TIMEOUT) { |
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30 | warn "nothign 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 | }; |
30 | }; |
35 | $w->timeout (10); |
31 | |
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32 | # SIGNALS |
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33 | |
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34 | my $w = EV::signal 'QUIT', sub { |
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35 | warn "sigquit received\n"; |
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36 | }; |
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37 | |
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38 | # CHILD/PID STATUS CHANGES |
36 | |
39 | |
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40 | my $w = EV::child 666, sub { |
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41 | my ($w, $revents) = @_; |
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42 | my $status = $w->rstatus; |
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43 | }; |
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44 | |
37 | # MAINLOOP |
45 | # MAINLOOP |
38 | EV::dispatch; # loop as long as watchers are active |
46 | EV::loop; # loop until EV::unloop is called or all watchers stop |
39 | EV::loop; # the same thing |
47 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
40 | EV::loop EV::LOOP_ONCE; |
48 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
41 | EV::loop EV::LOOP_ONSHOT; |
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42 | |
49 | |
43 | =head1 DESCRIPTION |
50 | =head1 DESCRIPTION |
44 | |
51 | |
45 | This module provides an interface to libevent |
52 | This module provides an interface to libev |
46 | (L<http://monkey.org/~provos/libevent/>). |
53 | (L<http://software.schmorp.de/pkg/libev.html>). |
47 | |
54 | |
48 | =cut |
55 | =cut |
49 | |
56 | |
50 | package EV; |
57 | package EV; |
51 | |
58 | |
52 | use strict; |
59 | use strict; |
53 | |
60 | |
54 | BEGIN { |
61 | BEGIN { |
55 | our $VERSION = '0.01'; |
62 | our $VERSION = '1.2'; |
56 | use XSLoader; |
63 | use XSLoader; |
57 | XSLoader::load "EV", $VERSION; |
64 | XSLoader::load "EV", $VERSION; |
58 | } |
65 | } |
59 | |
66 | |
60 | =head1 FUNCTIONAL INTERFACE |
67 | @EV::Io::ISA = |
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68 | @EV::Timer::ISA = |
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69 | @EV::Periodic::ISA = |
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70 | @EV::Signal::ISA = |
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71 | @EV::Idle::ISA = |
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72 | @EV::Prepare::ISA = |
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73 | @EV::Check::ISA = |
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74 | @EV::Child::ISA = "EV::Watcher"; |
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75 | |
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76 | =head1 BASIC INTERFACE |
61 | |
77 | |
62 | =over 4 |
78 | =over 4 |
63 | |
79 | |
64 | =item $EV::NPRI |
80 | =item $EV::DIED |
65 | |
81 | |
66 | How many priority levels are available. |
82 | Must contain a reference to a function that is called when a callback |
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83 | throws an exception (with $@ containing thr error). The default prints an |
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84 | informative message and continues. |
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85 | |
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86 | If this callback throws an exception it will be silently ignored. |
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87 | |
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88 | =item $time = EV::time |
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89 | |
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90 | Returns the current time in (fractional) seconds since the epoch. |
67 | |
91 | |
68 | =item $time = EV::now |
92 | =item $time = EV::now |
69 | |
93 | |
70 | Returns the time in (fractional) seconds since the epoch. |
94 | Returns the time the last event loop iteration has been started. This |
71 | |
95 | is the time that (relative) timers are based on, and refering to it is |
72 | =item $version = EV::version |
96 | usually faster then calling EV::time. |
73 | |
97 | |
74 | =item $method = EV::method |
98 | =item $method = EV::method |
75 | |
99 | |
76 | Return version string and event polling method used. |
100 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
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101 | or EV::METHOD_EPOLL). |
77 | |
102 | |
78 | =item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT |
103 | =item EV::loop [$flags] |
79 | |
104 | |
80 | =item EV::loopexit $after |
105 | Begin checking for events and calling callbacks. It returns when a |
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106 | callback calls EV::unloop. |
81 | |
107 | |
82 | Exit any active loop or dispatch after C<$after> seconds or immediately if |
108 | The $flags argument can be one of the following: |
83 | C<$after> is missing or zero. |
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84 | |
109 | |
85 | =item EV::dispatch |
110 | 0 as above |
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111 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
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112 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
86 | |
113 | |
87 | Same as C<EV::loop 0>. |
114 | =item EV::unloop [$how] |
88 | |
115 | |
89 | =item EV::event $callback |
116 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
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117 | innermost call to EV::loop return. |
90 | |
118 | |
91 | Creates a new event watcher waiting for nothing, calling the given callback. |
119 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
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120 | fast as possible. |
92 | |
121 | |
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122 | =back |
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123 | |
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124 | =head2 WATCHER |
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125 | |
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126 | A watcher is an object that gets created to record your interest in some |
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127 | event. For instance, if you want to wait for STDIN to become readable, you |
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128 | would create an EV::io watcher for that: |
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129 | |
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130 | my $watcher = EV::io *STDIN, EV::READ, sub { |
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131 | my ($watcher, $revents) = @_; |
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132 | warn "yeah, STDIN should not be readable without blocking!\n" |
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133 | }; |
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134 | |
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135 | All watchers can be active (waiting for events) or inactive (paused). Only |
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136 | active watchers will have their callbacks invoked. All callbacks will be |
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137 | called with at least two arguments: the watcher and a bitmask of received |
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138 | events. |
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139 | |
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140 | Each watcher type has its associated bit in revents, so you can use the |
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141 | same callback for multiple watchers. The event mask is named after the |
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142 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
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143 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
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144 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
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145 | uses EV::TIMEOUT). |
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146 | |
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147 | In the rare case where one wants to create a watcher but not start it at |
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148 | the same time, each constructor has a variant with a trailing C<_ns> in |
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149 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
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150 | |
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151 | Please note that a watcher will automatically be stopped when the watcher |
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152 | object is destroyed, so you I<need> to keep the watcher objects returned by |
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153 | the constructors. |
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154 | |
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155 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
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156 | ->fh and so on) automatically stop and start it again if it is active, |
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157 | which means pending events get lost. |
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158 | |
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159 | =head2 WATCHER TYPES |
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160 | |
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161 | Now lets move to the existing watcher types and asociated methods. |
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162 | |
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163 | The following methods are available for all watchers. Then followes a |
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164 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
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165 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
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166 | any type-specific methods (if any). |
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167 | |
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168 | =over 4 |
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169 | |
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170 | =item $w->start |
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171 | |
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172 | Starts a watcher if it isn't active already. Does nothing to an already |
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173 | active watcher. By default, all watchers start out in the active state |
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174 | (see the description of the C<_ns> variants if you need stopped watchers). |
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175 | |
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176 | =item $w->stop |
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177 | |
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178 | Stop a watcher if it is active. Also clear any pending events (events that |
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179 | have been received but that didn't yet result in a callback invocation), |
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180 | regardless of wether the watcher was active or not. |
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181 | |
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182 | =item $bool = $w->is_active |
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183 | |
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184 | Returns true if the watcher is active, false otherwise. |
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185 | |
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186 | =item $current_data = $w->data |
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187 | |
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188 | =item $old_data = $w->data ($new_data) |
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189 | |
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190 | Queries a freely usable data scalar on the watcher and optionally changes |
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191 | it. This is a way to associate custom data with a watcher: |
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192 | |
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193 | my $w = EV::timer 60, 0, sub { |
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194 | warn $_[0]->data; |
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195 | }; |
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196 | $w->data ("print me!"); |
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197 | |
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198 | =item $current_cb = $w->cb |
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199 | |
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200 | =item $old_cb = $w->cb ($new_cb) |
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201 | |
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202 | Queries the callback on the watcher and optionally changes it. You can do |
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203 | this at any time without the watcher restarting. |
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204 | |
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205 | =item $current_priority = $w->priority |
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206 | |
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207 | =item $old_priority = $w->priority ($new_priority) |
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208 | |
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209 | Queries the priority on the watcher and optionally changes it. Pending |
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210 | watchers with higher priority will be invoked first. The valid range of |
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211 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
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212 | -2). If the priority is outside this range it will automatically be |
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213 | normalised to the nearest valid priority. |
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214 | |
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215 | The default priority of any newly-created weatcher is 0. |
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216 | |
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217 | =item $w->trigger ($revents) |
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218 | |
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219 | Call the callback *now* with the given event mask. |
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220 | |
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221 | |
93 | =item my $w = EV::io $fileno_or_fh, $eventmask, $callback |
222 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
94 | |
223 | |
95 | =item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
224 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
96 | |
225 | |
97 | As long as the returned watcher object is alive, call the C<$callback> |
226 | As long as the returned watcher object is alive, call the C<$callback> |
98 | when the events specified in C<$eventmask> happen. Initially, the timeout |
227 | when the events specified in C<$eventmask>. |
99 | is disabled. |
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100 | |
228 | |
101 | The C<io_ns> variant doesn't add/start the newly created watcher. |
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102 | |
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103 | Eventmask can be one or more of these constants ORed together: |
229 | The $eventmask can be one or more of these constants ORed together: |
104 | |
230 | |
105 | EV::READ wait until read() wouldn't block anymore |
231 | EV::READ wait until read() wouldn't block anymore |
106 | EV::WRITE wait until write() wouldn't block anymore |
232 | EV::WRITE wait until write() wouldn't block anymore |
107 | EV::PERSIST stay active after an event occured |
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108 | |
233 | |
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234 | The C<io_ns> variant doesn't start (activate) the newly created watcher. |
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235 | |
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236 | =item $w->set ($fileno_or_fh, $eventmask) |
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237 | |
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238 | Reconfigures the watcher, see the constructor above for details. Can be |
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239 | called at any time. |
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240 | |
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241 | =item $current_fh = $w->fh |
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242 | |
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243 | =item $old_fh = $w->fh ($new_fh) |
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244 | |
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245 | Returns the previously set filehandle and optionally set a new one. |
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246 | |
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247 | =item $current_eventmask = $w->events |
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248 | |
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249 | =item $old_eventmask = $w->events ($new_eventmask) |
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250 | |
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251 | Returns the previously set event mask and optionally set a new one. |
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252 | |
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253 | |
109 | =item my $w = EV::timer $after, $repeat, $callback |
254 | =item $w = EV::timer $after, $repeat, $callback |
110 | |
255 | |
111 | =item my $w = EV::timer_ns $after, $repeat, $callback |
256 | =item $w = EV::timer_ns $after, $repeat, $callback |
112 | |
257 | |
113 | Calls the callback after C<$after> seconds. If C<$repeat> is true, the |
258 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
114 | timer will be restarted after the callback returns. This means that the |
259 | the timer will be restarted (with the $repeat value as $after) after the |
115 | callback would be called roughly every C<$after> seconds, prolonged by the |
260 | callback returns. |
116 | time the callback takes. |
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117 | |
261 | |
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262 | This means that the callback would be called roughly after C<$after> |
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263 | seconds, and then every C<$repeat> seconds. The timer does his best not |
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264 | to drift, but it will not invoke the timer more often then once per event |
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265 | loop iteration, and might drift in other cases. If that isn't acceptable, |
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266 | look at EV::periodic, which can provide long-term stable timers. |
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267 | |
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268 | The timer is based on a monotonic clock, that is, if somebody is sitting |
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269 | in front of the machine while the timer is running and changes the system |
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270 | clock, the timer will nevertheless run (roughly) the same time. |
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271 | |
118 | The C<timer_ns> variant doesn't add/start the newly created watcher. |
272 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
119 | |
273 | |
120 | =item my $w = EV::timer_abs $at, $interval, $callback |
274 | =item $w->set ($after, $repeat) |
121 | |
275 | |
122 | =item my $w = EV::timer_abs_ns $at, $interval, $callback |
276 | Reconfigures the watcher, see the constructor above for details. Can be at |
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277 | any time. |
123 | |
278 | |
124 | Similar to EV::timer, but the time is given as an absolute point in time |
279 | =item $w->again |
125 | (C<$at>), plus an optional C<$interval>. |
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126 | |
280 | |
127 | If the C<$interval> is zero, then the callback will be called at the time |
281 | Similar to the C<start> method, but has special semantics for repeating timers: |
128 | C<$at> if that is in the future, or as soon as possible if its in the |
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129 | past. It will not automatically repeat. |
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130 | |
282 | |
131 | If the C<$interval> is nonzero, then the watcher will always be scheduled |
283 | If the timer is active and non-repeating, it will be stopped. |
132 | to time out at the next C<$at + integer * $interval> time. |
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133 | |
284 | |
134 | This can be used to schedule a callback to run at very regular intervals, |
285 | If the timer is active and repeating, reset the timeout to occur |
135 | as long as the processing time is less then the interval (otherwise |
286 | C<$repeat> seconds after now. |
136 | obviously events will be skipped). |
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137 | |
287 | |
138 | The C<timer_abs_ns> variant doesn't add/start the newly created watcher. |
288 | If the timer is inactive and repeating, start it using the repeat value. |
139 | |
289 | |
140 | =item my $w = EV::signal $signum, $callback |
290 | Otherwise do nothing. |
141 | |
291 | |
142 | =item my $w = EV::signal_ns $signum, $callback |
292 | This behaviour is useful when you have a timeout for some IO |
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293 | operation. You create a timer object with the same value for C<$after> and |
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294 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
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295 | on the timeout. |
143 | |
296 | |
144 | Call the callback when signal $signum is received. |
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145 | |
297 | |
146 | The C<signal_ns> variant doesn't add/start the newly created watcher. |
298 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
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299 | |
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300 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
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301 | |
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302 | Similar to EV::timer, but is not based on relative timeouts but on |
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303 | absolute times. Apart from creating "simple" timers that trigger "at" the |
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304 | specified time, it can also be used for non-drifting absolute timers and |
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305 | more complex, cron-like, setups that are not adversely affected by time |
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306 | jumps (i.e. when the system clock is changed by explicit date -s or other |
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307 | means such as ntpd). It is also the most complex watcher type in EV. |
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308 | |
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309 | It has three distinct "modes": |
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310 | |
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311 | =over 4 |
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312 | |
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313 | =item * absolute timer ($interval = $reschedule_cb = 0) |
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314 | |
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315 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
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316 | will not adjust when a time jump occurs, that is, if it is to be run |
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317 | at January 1st 2011 then it will run when the system time reaches or |
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318 | surpasses this time. |
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319 | |
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320 | =item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
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321 | |
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322 | In this mode the watcher will always be scheduled to time out at the |
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323 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
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324 | regardless of any time jumps. |
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325 | |
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326 | This can be used to create timers that do not drift with respect to system |
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327 | time: |
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328 | |
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329 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
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330 | |
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331 | That doesn't mean there will always be 3600 seconds in between triggers, |
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332 | but only that the the clalback will be called when the system time shows a |
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333 | full hour (UTC). |
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334 | |
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335 | Another way to think about it (for the mathematically inclined) is that |
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336 | EV::periodic will try to run the callback in this mode at the next |
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337 | possible time where C<$time = $at (mod $interval)>, regardless of any time |
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338 | jumps. |
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339 | |
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340 | =item * manual reschedule mode ($reschedule_cb = coderef) |
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341 | |
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342 | In this mode $interval and $at are both being ignored. Instead, each |
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343 | time the periodic watcher gets scheduled, the reschedule callback |
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344 | ($reschedule_cb) will be called with the watcher as first, and the current |
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345 | time as second argument. |
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346 | |
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347 | I<This callback MUST NOT stop or destroy this or any other periodic |
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348 | watcher, ever>. If you need to stop it, return 1e30 and stop it |
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349 | afterwards. |
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350 | |
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351 | It must return the next time to trigger, based on the passed time value |
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352 | (that is, the lowest time value larger than to the second argument). It |
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353 | will usually be called just before the callback will be triggered, but |
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354 | might be called at other times, too. |
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355 | |
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356 | This can be used to create very complex timers, such as a timer that |
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357 | triggers on each midnight, local time (actually 24 hours after the last |
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358 | midnight, to keep the example simple. If you know a way to do it correctly |
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359 | in about the same space (without requiring elaborate modules), drop me a |
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360 | note :): |
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361 | |
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362 | my $daily = EV::periodic 0, 0, sub { |
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363 | my ($w, $now) = @_; |
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364 | |
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365 | use Time::Local (); |
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366 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
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367 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
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368 | }, sub { |
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369 | print "it's midnight or likely shortly after, now\n"; |
|
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370 | }; |
147 | |
371 | |
148 | =back |
372 | =back |
149 | |
373 | |
150 | =head1 THE EV::Event CLASS |
374 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
151 | |
375 | |
152 | All EV functions creating an event watcher (designated by C<my $w => |
376 | =item $w->set ($at, $interval, $reschedule_cb) |
153 | above) support the following methods on the returned watcher object: |
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154 | |
377 | |
155 | =over 4 |
378 | Reconfigures the watcher, see the constructor above for details. Can be at |
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379 | any time. |
156 | |
380 | |
157 | =item $w->add ($timeout) |
381 | =item $w->again |
158 | |
382 | |
159 | Stops and (re-)starts the event watcher, setting the optional timeout to |
383 | Simply stops and starts the watcher again. |
160 | the given value, or clearing the timeout if none is given. |
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161 | |
384 | |
162 | =item $w->start |
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163 | |
385 | |
164 | Stops and (re-)starts the event watcher without touching the timeout. |
386 | =item $w = EV::signal $signal, $callback |
165 | |
387 | |
166 | =item $w->del |
388 | =item $w = EV::signal_ns $signal, $callback |
167 | |
389 | |
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390 | Call the callback when $signal is received (the signal can be specified |
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391 | by number or by name, just as with kill or %SIG). |
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392 | |
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393 | EV will grab the signal for the process (the kernel only allows one |
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394 | component to receive a signal at a time) when you start a signal watcher, |
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395 | and removes it again when you stop it. Perl does the same when you |
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396 | add/remove callbacks to %SIG, so watch out. |
|
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397 | |
|
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398 | You can have as many signal watchers per signal as you want. |
|
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399 | |
|
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400 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
|
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401 | |
|
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402 | =item $w->set ($signal) |
|
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403 | |
|
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404 | Reconfigures the watcher, see the constructor above for details. Can be at |
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405 | any time. |
|
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406 | |
|
|
407 | =item $current_signum = $w->signal |
|
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408 | |
|
|
409 | =item $old_signum = $w->signal ($new_signal) |
|
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410 | |
|
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411 | Returns the previously set signal (always as a number not name) and |
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412 | optionally set a new one. |
|
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413 | |
|
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414 | |
|
|
415 | =item $w = EV::child $pid, $callback |
|
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416 | |
|
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417 | =item $w = EV::child_ns $pid, $callback |
|
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418 | |
|
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419 | Call the callback when a status change for pid C<$pid> (or any pid |
|
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420 | if C<$pid> is 0) has been received. More precisely: when the process |
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421 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
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422 | changed/zombie children and call the callback. |
|
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423 | |
|
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424 | You can access both status and pid by using the C<rstatus> and C<rpid> |
|
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425 | methods on the watcher object. |
|
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426 | |
|
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427 | You can have as many pid watchers per pid as you want. |
|
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428 | |
|
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429 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
|
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430 | |
168 | =item $w->stop |
431 | =item $w->set ($pid) |
169 | |
432 | |
170 | Stop the event watcher if it was started. |
433 | Reconfigures the watcher, see the constructor above for details. Can be at |
|
|
434 | any time. |
171 | |
435 | |
172 | =item $current_callback = $w->cb |
|
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173 | |
|
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174 | =item $old_callback = $w->cb ($new_callback) |
|
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175 | |
|
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176 | Return the previously set callback and optionally set a new one. |
|
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177 | |
|
|
178 | =item $current_fh = $w->fh |
436 | =item $current_pid = $w->pid |
179 | |
437 | |
180 | =item $old_fh = $w->fh ($new_fh) |
438 | =item $old_pid = $w->pid ($new_pid) |
181 | |
439 | |
182 | Returns the previously set filehandle and optionally set a new one. |
|
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183 | |
|
|
184 | =item $current_eventmask = $w->events |
|
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185 | |
|
|
186 | =item $old_eventmask = $w->events ($new_eventmask) |
|
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187 | |
|
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188 | Returns the previously set event mask and optionally set a new one. |
440 | Returns the previously set process id and optionally set a new one. |
189 | |
441 | |
190 | =item $w->timeout ($after, $repeat) |
442 | =item $exit_status = $w->rstatus |
191 | |
443 | |
192 | Resets the timeout (see C<EV::timer> for details). |
444 | Return the exit/wait status (as returned by waitpid, see the waitpid entry |
|
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445 | in perlfunc). |
193 | |
446 | |
194 | =item $w->timeout_abs ($at, $interval) |
447 | =item $pid = $w->rpid |
195 | |
448 | |
196 | Resets the timeout (see C<EV::timer_abs> for details). |
449 | Return the pid of the awaited child (useful when you have installed a |
|
|
450 | watcher for all pids). |
197 | |
451 | |
198 | =item $w->priority_set ($priority) |
|
|
199 | |
452 | |
200 | Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI). |
453 | =item $w = EV::idle $callback |
|
|
454 | |
|
|
455 | =item $w = EV::idle_ns $callback |
|
|
456 | |
|
|
457 | Call the callback when there are no pending io, timer/periodic, signal or |
|
|
458 | child events, i.e. when the process is idle. |
|
|
459 | |
|
|
460 | The process will not block as long as any idle watchers are active, and |
|
|
461 | they will be called repeatedly until stopped. |
|
|
462 | |
|
|
463 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
|
|
464 | |
|
|
465 | |
|
|
466 | =item $w = EV::prepare $callback |
|
|
467 | |
|
|
468 | =item $w = EV::prepare_ns $callback |
|
|
469 | |
|
|
470 | Call the callback just before the process would block. You can still |
|
|
471 | create/modify any watchers at this point. |
|
|
472 | |
|
|
473 | See the EV::check watcher, below, for explanations and an example. |
|
|
474 | |
|
|
475 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
|
|
476 | |
|
|
477 | |
|
|
478 | =item $w = EV::check $callback |
|
|
479 | |
|
|
480 | =item $w = EV::check_ns $callback |
|
|
481 | |
|
|
482 | Call the callback just after the process wakes up again (after it has |
|
|
483 | gathered events), but before any other callbacks have been invoked. |
|
|
484 | |
|
|
485 | This is used to integrate other event-based software into the EV |
|
|
486 | mainloop: You register a prepare callback and in there, you create io and |
|
|
487 | timer watchers as required by the other software. Here is a real-world |
|
|
488 | example of integrating Net::SNMP (with some details left out): |
|
|
489 | |
|
|
490 | our @snmp_watcher; |
|
|
491 | |
|
|
492 | our $snmp_prepare = EV::prepare sub { |
|
|
493 | # do nothing unless active |
|
|
494 | $dispatcher->{_event_queue_h} |
|
|
495 | or return; |
|
|
496 | |
|
|
497 | # make the dispatcher handle any outstanding stuff |
|
|
498 | ... not shown |
|
|
499 | |
|
|
500 | # create an IO watcher for each and every socket |
|
|
501 | @snmp_watcher = ( |
|
|
502 | (map { EV::io $_, EV::READ, sub { } } |
|
|
503 | keys %{ $dispatcher->{_descriptors} }), |
|
|
504 | |
|
|
505 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
506 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
507 | 0, sub { }, |
|
|
508 | ); |
|
|
509 | }; |
|
|
510 | |
|
|
511 | The callbacks are irrelevant (and are not even being called), the |
|
|
512 | only purpose of those watchers is to wake up the process as soon as |
|
|
513 | one of those events occurs (socket readable, or timer timed out). The |
|
|
514 | corresponding EV::check watcher will then clean up: |
|
|
515 | |
|
|
516 | our $snmp_check = EV::check sub { |
|
|
517 | # destroy all watchers |
|
|
518 | @snmp_watcher = (); |
|
|
519 | |
|
|
520 | # make the dispatcher handle any new stuff |
|
|
521 | ... not shown |
|
|
522 | }; |
|
|
523 | |
|
|
524 | The callbacks of the created watchers will not be called as the watchers |
|
|
525 | are destroyed before this cna happen (remember EV::check gets called |
|
|
526 | first). |
|
|
527 | |
|
|
528 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
201 | |
529 | |
202 | =back |
530 | =back |
203 | |
531 | |
204 | =head1 BUGS |
532 | =head1 THREADS |
205 | |
533 | |
206 | Lots. Libevent itself isn't well tested and rather buggy, and this module |
534 | Threads are not supported by this module in any way. Perl pseudo-threads |
207 | is quite new at the moment. |
535 | is evil stuff and must die. As soon as Perl gains real threads I will work |
|
|
536 | on thread support for it. |
|
|
537 | |
|
|
538 | =head1 FORK |
|
|
539 | |
|
|
540 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
541 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
542 | not supported and usually destructive). Libev makes it possible to work |
|
|
543 | around this by having a function that recreates the kernel state after |
|
|
544 | fork in the child. |
|
|
545 | |
|
|
546 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
547 | functionality to do this automatically for you. This function is quite |
|
|
548 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
549 | negligible, because everything the function currently does is set a flag |
|
|
550 | that is checked only when the event loop gets used the next time, so when |
|
|
551 | you do fork but not use EV, the overhead is minimal. |
|
|
552 | |
|
|
553 | On win32, there is no notion of fork so all this doesn't apply, of course. |
208 | |
554 | |
209 | =cut |
555 | =cut |
210 | |
556 | |
211 | our $NPRI = 4; |
557 | our $DIED = sub { |
212 | our $BASE = init; |
558 | warn "EV: error in callback (ignoring): $@"; |
213 | priority_init $NPRI; |
559 | }; |
214 | |
560 | |
215 | push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"]; |
561 | default_loop |
|
|
562 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
216 | |
563 | |
217 | 1; |
564 | 1; |
218 | |
565 | |
219 | =head1 SEE ALSO |
566 | =head1 SEE ALSO |
220 | |
567 | |
221 | L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>. |
568 | L<EV::DNS>. |
222 | L<EV::AnyEvent>. |
|
|
223 | |
569 | |
224 | =head1 AUTHOR |
570 | =head1 AUTHOR |
225 | |
571 | |
226 | Marc Lehmann <schmorp@schmorp.de> |
572 | Marc Lehmann <schmorp@schmorp.de> |
227 | http://home.schmorp.de/ |
573 | http://home.schmorp.de/ |