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=head1 NAME |
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EV - perl interface to libev, a high performance full-featured event loop |
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=head1 SYNOPSIS |
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use EV; |
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# TIMERS |
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my $w = EV::timer 2, 0, sub { |
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warn "is called after 2s"; |
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}; |
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my $w = EV::timer 2, 2, sub { |
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warn "is called roughly every 2s (repeat = 2)"; |
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}; |
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undef $w; # destroy event watcher again |
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my $w = EV::periodic 0, 60, 0, sub { |
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warn "is called every minute, on the minute, exactly"; |
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}; |
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# IO |
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my $w = EV::io *STDIN, EV::READ, sub { |
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my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
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warn "stdin is readable, you entered: ", ; |
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}; |
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# SIGNALS |
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my $w = EV::signal 'QUIT', sub { |
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warn "sigquit received\n"; |
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}; |
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# CHILD/PID STATUS CHANGES |
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my $w = EV::child 666, 0, sub { |
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my ($w, $revents) = @_; |
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my $status = $w->rstatus; |
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}; |
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# STAT CHANGES |
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my $w = EV::stat "/etc/passwd", 10, sub { |
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my ($w, $revents) = @_; |
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warn $w->path, " has changed somehow.\n"; |
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}; |
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# MAINLOOP |
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EV::run; # loop until EV::break is called or all watchers stop |
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EV::run EV::RUN_ONCE; # block until at least one event could be handled |
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EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block |
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=head1 BEFORE YOU START USING THIS MODULE |
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If you only need timer, I/O, signal, child and idle watchers and not the |
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advanced functionality of this module, consider using L instead, |
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specifically the simplified API described in L. |
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When used with EV as backend, the L API is as fast as the native L |
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API, but your programs/modules will still run with many other event loops. |
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=head1 DESCRIPTION |
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This module provides an interface to libev |
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(L). While the documentation |
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below is comprehensive, one might also consult the documentation of |
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libev itself (L or |
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F) for more subtle details on watcher semantics or some |
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discussion on the available backends, or how to force a specific backend |
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with C, or just about in any case because it has much more |
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detailed information. |
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This module is very fast and scalable. It is actually so fast that you |
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can use it through the L module, stay portable to other event |
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loops (if you don't rely on any watcher types not available through it) |
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and still be faster than with any other event loop currently supported in |
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Perl. |
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82
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=head2 PORTING FROM EV 3.X to 4.X |
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84
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EV version 4 introduces a number of incompatible changes summarised |
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here. According to the depreciation strategy used by libev, there is a |
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compatibility layer in place so programs should continue to run unchanged |
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(the XS interface lacks this layer, so programs using that one need to be |
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updated). |
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This compatibility layer will be switched off in some future release. |
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92
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All changes relevant to Perl are renames of symbols, functions and |
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methods: |
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EV::loop => EV::run |
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EV::LOOP_NONBLOCK => EV::RUN_NOWAIT |
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EV::LOOP_ONESHOT => EV::RUN_ONCE |
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EV::unloop => EV::break |
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EV::UNLOOP_CANCEL => EV::BREAK_CANCEL |
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EV::UNLOOP_ONE => EV::BREAK_ONE |
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EV::UNLOOP_ALL => EV::BREAK_ALL |
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104
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EV::TIMEOUT => EV::TIMER |
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EV::loop_count => EV::iteration |
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EV::loop_depth => EV::depth |
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EV::loop_verify => EV::verify |
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110
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The loop object methods corresponding to the functions above have been |
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similarly renamed. |
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113
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=head2 MODULE EXPORTS |
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115
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This module does not export any symbols. |
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117
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=cut |
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119
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package EV; |
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121
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use common::sense; |
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122
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123
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BEGIN { |
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our $VERSION = '4.32'; |
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use XSLoader; |
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local $^W = 0; # avoid spurious warning |
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XSLoader::load "EV", $VERSION; |
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} |
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130
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@EV::IO::ISA = |
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@EV::Timer::ISA = |
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@EV::Periodic::ISA = |
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@EV::Signal::ISA = |
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@EV::Child::ISA = |
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@EV::Stat::ISA = |
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@EV::Idle::ISA = |
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@EV::Prepare::ISA = |
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@EV::Check::ISA = |
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@EV::Embed::ISA = |
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@EV::Fork::ISA = |
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@EV::Async::ISA = |
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"EV::Watcher"; |
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@EV::Loop::Default::ISA = "EV::Loop"; |
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146
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=head1 EVENT LOOPS |
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148
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EV supports multiple event loops: There is a single "default event loop" |
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that can handle everything including signals and child watchers, and any |
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number of "dynamic event loops" that can use different backends (with |
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various limitations), but no child and signal watchers. |
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153
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You do not have to do anything to create the default event loop: When |
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the module is loaded a suitable backend is selected on the premise of |
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selecting a working backend (which for example rules out kqueue on most |
156
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BSDs). Modules should, unless they have "special needs" always use the |
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default loop as this is fastest (perl-wise), best supported by other |
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modules (e.g. AnyEvent or Coro) and most portable event loop. |
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160
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For specific programs you can create additional event loops dynamically. |
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162
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If you want to take advantage of kqueue (which often works properly for |
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sockets only) even though the default loop doesn't enable it, you can |
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I |
165
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will then also service the kqueue loop to some extent. See the example in |
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the section about embed watchers for an example on how to achieve that. |
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168
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=over 4 |
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170
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=item $loop = new EV::Loop [$flags] |
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172
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Create a new event loop as per the specified flags. Please refer to |
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the C function description in the libev documentation |
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(L, |
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or locally-installed as F manpage) for more info. |
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177
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The loop will automatically be destroyed when it is no longer referenced |
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by any watcher and the loop object goes out of scope. |
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180
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If you are not embedding the loop, then Using C |
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is recommended, as only the default event loop is protected by this |
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module. If you I embedding this loop in the default loop, this is not |
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necessary, as C automatically does the right thing on fork. |
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185
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=item $loop->loop_fork |
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187
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Must be called after a fork in the child, before entering or continuing |
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the event loop. An alternative is to use C which calls |
189
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this function automatically, at some performance loss (refer to the libev |
190
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documentation). |
191
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192
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=item $loop->verify |
193
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194
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Calls C to make internal consistency checks (for debugging |
195
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libev) and abort the program if any data structures were found to be |
196
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corrupted. |
197
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198
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=item $loop = EV::default_loop [$flags] |
199
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200
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Return the default loop (which is a singleton object). Since this module |
201
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already creates the default loop with default flags, specifying flags here |
202
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will not have any effect unless you destroy the default loop first, which |
203
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isn't supported. So in short: don't do it, and if you break it, you get to |
204
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keep the pieces. |
205
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206
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=back |
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208
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209
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=head1 BASIC INTERFACE |
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211
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=over 4 |
212
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213
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=item $EV::DIED |
214
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215
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Must contain a reference to a function that is called when a callback |
216
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throws an exception (with $@ containing the error). The default prints an |
217
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informative message and continues. |
218
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219
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If this callback throws an exception it will be silently ignored. |
220
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221
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=item $flags = EV::supported_backends |
222
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223
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=item $flags = EV::recommended_backends |
224
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225
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=item $flags = EV::embeddable_backends |
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227
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Returns the set (see C flags) of backends supported by this |
228
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instance of EV, the set of recommended backends (supposed to be good) for |
229
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this platform and the set of embeddable backends (see EMBED WATCHERS). |
230
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231
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=item EV::sleep $seconds |
232
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233
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Block the process for the given number of (fractional) seconds. |
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=item $time = EV::time |
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Returns the current time in (fractional) seconds since the epoch. |
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=item $time = EV::now |
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=item $time = $loop->now |
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Returns the time the last event loop iteration has been started. This |
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is the time that (relative) timers are based on, and referring to it is |
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usually faster then calling EV::time. |
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=item EV::now_update |
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249
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=item $loop->now_update |
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Establishes the current time by querying the kernel, updating the time |
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returned by C in the progress. This is a costly operation and |
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is usually done automatically within C. |
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255
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This function is rarely useful, but when some event callback runs for a |
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very long time without entering the event loop, updating libev's idea of |
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the current time is a good idea. |
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=item EV::suspend |
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261
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=item $loop->suspend |
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=item EV::resume |
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265
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=item $loop->resume |
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These two functions suspend and resume a loop, for use when the loop is |
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not used for a while and timeouts should not be processed. |
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270
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A typical use case would be an interactive program such as a game: When |
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the user presses C<^Z> to suspend the game and resumes it an hour later it |
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would be best to handle timeouts as if no time had actually passed while |
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the program was suspended. This can be achieved by calling C |
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in your C handler, sending yourself a C and calling |
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C directly afterwards to resume timer processing. |
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277
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Effectively, all C watchers will be delayed by the time spend |
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between C and C, and all C watchers |
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will be rescheduled (that is, they will lose any events that would have |
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occured while suspended). |
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282
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After calling C you B call I function on the given |
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loop other than C, and you B call C |
284
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without a previous call to C. |
285
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286
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Calling C/C has the side effect of updating the event |
287
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loop time (see C). |
288
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289
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=item $backend = EV::backend |
290
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291
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=item $backend = $loop->backend |
292
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293
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Returns an integer describing the backend used by libev (EV::BACKEND_SELECT |
294
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or EV::BACKEND_EPOLL). |
295
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296
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=item $active = EV::run [$flags] |
297
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298
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=item $active = $loop->run ([$flags]) |
299
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300
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Begin checking for events and calling callbacks. It returns when a |
301
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callback calls EV::break or the flags are nonzero (in which case the |
302
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return value is true) or when there are no active watchers which reference |
303
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the loop (keepalive is true), in which case the return value will be |
304
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false. The return value can generally be interpreted as "if true, there is |
305
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more work left to do". |
306
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307
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The $flags argument can be one of the following: |
308
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309
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0 as above |
310
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EV::RUN_ONCE block at most once (wait, but do not loop) |
311
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EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait) |
312
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313
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=item EV::break [$how] |
314
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315
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=item $loop->break ([$how]) |
316
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317
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When called with no arguments or an argument of EV::BREAK_ONE, makes the |
318
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innermost call to EV::run return. |
319
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320
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When called with an argument of EV::BREAK_ALL, all calls to EV::run will |
321
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return as fast as possible. |
322
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323
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When called with an argument of EV::BREAK_CANCEL, any pending break will |
324
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be cancelled. |
325
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326
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=item $count = EV::iteration |
327
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328
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=item $count = $loop->iteration |
329
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330
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Return the number of times the event loop has polled for new |
331
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events. Sometimes useful as a generation counter. |
332
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333
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=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
334
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335
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=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
336
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337
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This function rolls together an I/O and a timer watcher for a single |
338
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one-shot event without the need for managing a watcher object. |
339
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340
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If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
341
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must be a bitset containing either C, C or C
|
342
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| EV::WRITE>, indicating the type of I/O event you want to wait for. If |
343
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you do not want to wait for some I/O event, specify C for |
344
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C<$fh_or_undef> and C<0> for C<$events>). |
345
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346
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If timeout is C or negative, then there will be no |
347
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timeout. Otherwise an C with this value will be started. |
348
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349
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When an error occurs or either the timeout or I/O watcher triggers, then |
350
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the callback will be called with the received event set (in general |
351
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|
you can expect it to be a combination of C, C, |
352
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C and C). |
353
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354
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EV::once doesn't return anything: the watchers stay active till either |
355
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of them triggers, then they will be stopped and freed, and the callback |
356
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invoked. |
357
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358
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=item EV::feed_fd_event $fd, $revents |
359
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360
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=item $loop->feed_fd_event ($fd, $revents) |
361
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362
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|
Feed an event on a file descriptor into EV. EV will react to this call as |
363
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|
|
if the readyness notifications specified by C<$revents> (a combination of |
364
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|
C and C) happened on the file descriptor C<$fd>. |
365
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366
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=item EV::feed_signal_event $signal |
367
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368
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|
|
Feed a signal event into the default loop. EV will react to this call as |
369
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|
if the signal specified by C<$signal> had occured. |
370
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371
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=item EV::feed_signal $signal |
372
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373
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|
Feed a signal event into EV - unlike C, this works |
374
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|
regardless of which loop has registered the signal, and is mainly useful |
375
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|
for custom signal implementations. |
376
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377
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|
=item EV::set_io_collect_interval $time |
378
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379
|
|
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|
|
=item $loop->set_io_collect_interval ($time) |
380
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381
|
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|
|
=item EV::set_timeout_collect_interval $time |
382
|
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383
|
|
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|
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|
|
=item $loop->set_timeout_collect_interval ($time) |
384
|
|
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|
385
|
|
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|
|
|
|
These advanced functions set the minimum block interval when polling for I/O events and the minimum |
386
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|
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|
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|
|
wait interval for timer events. See the libev documentation at |
387
|
|
|
|
|
|
|
L |
388
|
|
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|
|
|
|
(locally installed as F) for a more detailed discussion. |
389
|
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|
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390
|
|
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|
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|
|
=item $count = EV::pending_count |
391
|
|
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|
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|
|
392
|
|
|
|
|
|
|
=item $count = $loop->pending_count |
393
|
|
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|
|
|
|
|
394
|
|
|
|
|
|
|
Returns the number of currently pending watchers. |
395
|
|
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|
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|
|
396
|
|
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|
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|
|
=item EV::invoke_pending |
397
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|
398
|
|
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|
|
|
|
=item $loop->invoke_pending |
399
|
|
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|
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|
|
|
400
|
|
|
|
|
|
|
Invoke all currently pending watchers. |
401
|
|
|
|
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|
|
|
402
|
|
|
|
|
|
|
=back |
403
|
|
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|
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|
|
|
404
|
|
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|
|
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405
|
|
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|
|
|
|
=head1 WATCHER OBJECTS |
406
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|
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|
|
|
|
|
407
|
|
|
|
|
|
|
A watcher is an object that gets created to record your interest in some |
408
|
|
|
|
|
|
|
event. For instance, if you want to wait for STDIN to become readable, you |
409
|
|
|
|
|
|
|
would create an EV::io watcher for that: |
410
|
|
|
|
|
|
|
|
411
|
|
|
|
|
|
|
my $watcher = EV::io *STDIN, EV::READ, sub { |
412
|
|
|
|
|
|
|
my ($watcher, $revents) = @_; |
413
|
|
|
|
|
|
|
warn "yeah, STDIN should now be readable without blocking!\n" |
414
|
|
|
|
|
|
|
}; |
415
|
|
|
|
|
|
|
|
416
|
|
|
|
|
|
|
All watchers can be active (waiting for events) or inactive (paused). Only |
417
|
|
|
|
|
|
|
active watchers will have their callbacks invoked. All callbacks will be |
418
|
|
|
|
|
|
|
called with at least two arguments: the watcher and a bitmask of received |
419
|
|
|
|
|
|
|
events. |
420
|
|
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|
|
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421
|
|
|
|
|
|
|
Each watcher type has its associated bit in revents, so you can use the |
422
|
|
|
|
|
|
|
same callback for multiple watchers. The event mask is named after the |
423
|
|
|
|
|
|
|
type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
424
|
|
|
|
|
|
|
EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
425
|
|
|
|
|
|
|
(which can set both EV::READ and EV::WRITE bits). |
426
|
|
|
|
|
|
|
|
427
|
|
|
|
|
|
|
In the rare case where one wants to create a watcher but not start it at |
428
|
|
|
|
|
|
|
the same time, each constructor has a variant with a trailing C<_ns> in |
429
|
|
|
|
|
|
|
its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
430
|
|
|
|
|
|
|
|
431
|
|
|
|
|
|
|
Please note that a watcher will automatically be stopped when the watcher |
432
|
|
|
|
|
|
|
object is destroyed, so you I to keep the watcher objects returned by |
433
|
|
|
|
|
|
|
the constructors. |
434
|
|
|
|
|
|
|
|
435
|
|
|
|
|
|
|
Also, all methods changing some aspect of a watcher (->set, ->priority, |
436
|
|
|
|
|
|
|
->fh and so on) automatically stop and start it again if it is active, |
437
|
|
|
|
|
|
|
which means pending events get lost. |
438
|
|
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|
|
|
|
|
439
|
|
|
|
|
|
|
=head2 COMMON WATCHER METHODS |
440
|
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|
|
|
|
|
|
441
|
|
|
|
|
|
|
This section lists methods common to all watchers. |
442
|
|
|
|
|
|
|
|
443
|
|
|
|
|
|
|
=over 4 |
444
|
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|
|
445
|
|
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|
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|
|
=item $w->start |
446
|
|
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|
|
|
|
|
447
|
|
|
|
|
|
|
Starts a watcher if it isn't active already. Does nothing to an already |
448
|
|
|
|
|
|
|
active watcher. By default, all watchers start out in the active state |
449
|
|
|
|
|
|
|
(see the description of the C<_ns> variants if you need stopped watchers). |
450
|
|
|
|
|
|
|
|
451
|
|
|
|
|
|
|
=item $w->stop |
452
|
|
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|
|
|
|
|
453
|
|
|
|
|
|
|
Stop a watcher if it is active. Also clear any pending events (events that |
454
|
|
|
|
|
|
|
have been received but that didn't yet result in a callback invocation), |
455
|
|
|
|
|
|
|
regardless of whether the watcher was active or not. |
456
|
|
|
|
|
|
|
|
457
|
|
|
|
|
|
|
=item $bool = $w->is_active |
458
|
|
|
|
|
|
|
|
459
|
|
|
|
|
|
|
Returns true if the watcher is active, false otherwise. |
460
|
|
|
|
|
|
|
|
461
|
|
|
|
|
|
|
=item $current_data = $w->data |
462
|
|
|
|
|
|
|
|
463
|
|
|
|
|
|
|
=item $old_data = $w->data ($new_data) |
464
|
|
|
|
|
|
|
|
465
|
|
|
|
|
|
|
Queries a freely usable data scalar on the watcher and optionally changes |
466
|
|
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|
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|
|
it. This is a way to associate custom data with a watcher: |
467
|
|
|
|
|
|
|
|
468
|
|
|
|
|
|
|
my $w = EV::timer 60, 0, sub { |
469
|
|
|
|
|
|
|
warn $_[0]->data; |
470
|
|
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|
|
|
|
}; |
471
|
|
|
|
|
|
|
$w->data ("print me!"); |
472
|
|
|
|
|
|
|
|
473
|
|
|
|
|
|
|
=item $current_cb = $w->cb |
474
|
|
|
|
|
|
|
|
475
|
|
|
|
|
|
|
=item $old_cb = $w->cb ($new_cb) |
476
|
|
|
|
|
|
|
|
477
|
|
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|
|
|
|
Queries the callback on the watcher and optionally changes it. You can do |
478
|
|
|
|
|
|
|
this at any time without the watcher restarting. |
479
|
|
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|
|
|
|
|
480
|
|
|
|
|
|
|
=item $current_priority = $w->priority |
481
|
|
|
|
|
|
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|
482
|
|
|
|
|
|
|
=item $old_priority = $w->priority ($new_priority) |
483
|
|
|
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|
|
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|
484
|
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|
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|
Queries the priority on the watcher and optionally changes it. Pending |
485
|
|
|
|
|
|
|
watchers with higher priority will be invoked first. The valid range of |
486
|
|
|
|
|
|
|
priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
487
|
|
|
|
|
|
|
-2). If the priority is outside this range it will automatically be |
488
|
|
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|
|
|
|
normalised to the nearest valid priority. |
489
|
|
|
|
|
|
|
|
490
|
|
|
|
|
|
|
The default priority of any newly-created watcher is 0. |
491
|
|
|
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|
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|
492
|
|
|
|
|
|
|
Note that the priority semantics have not yet been fleshed out and are |
493
|
|
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|
|
|
|
subject to almost certain change. |
494
|
|
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|
|
|
|
|
495
|
|
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|
|
|
|
=item $w->invoke ($revents) |
496
|
|
|
|
|
|
|
|
497
|
|
|
|
|
|
|
Call the callback *now* with the given event mask. |
498
|
|
|
|
|
|
|
|
499
|
|
|
|
|
|
|
=item $w->feed_event ($revents) |
500
|
|
|
|
|
|
|
|
501
|
|
|
|
|
|
|
Feed some events on this watcher into EV. EV will react to this call as if |
502
|
|
|
|
|
|
|
the watcher had received the given C<$revents> mask. |
503
|
|
|
|
|
|
|
|
504
|
|
|
|
|
|
|
=item $revents = $w->clear_pending |
505
|
|
|
|
|
|
|
|
506
|
|
|
|
|
|
|
If the watcher is pending, this function clears its pending status and |
507
|
|
|
|
|
|
|
returns its C<$revents> bitset (as if its callback was invoked). If the |
508
|
|
|
|
|
|
|
watcher isn't pending it does nothing and returns C<0>. |
509
|
|
|
|
|
|
|
|
510
|
|
|
|
|
|
|
=item $previous_state = $w->keepalive ($bool) |
511
|
|
|
|
|
|
|
|
512
|
|
|
|
|
|
|
Normally, C will return when there are no active watchers |
513
|
|
|
|
|
|
|
(which is a "deadlock" because no progress can be made anymore). This is |
514
|
|
|
|
|
|
|
convenient because it allows you to start your watchers (and your jobs), |
515
|
|
|
|
|
|
|
call C once and when it returns you know that all your jobs are |
516
|
|
|
|
|
|
|
finished (or they forgot to register some watchers for their task :). |
517
|
|
|
|
|
|
|
|
518
|
|
|
|
|
|
|
Sometimes, however, this gets in your way, for example when the module |
519
|
|
|
|
|
|
|
that calls C (usually the main program) is not the same module |
520
|
|
|
|
|
|
|
as a long-living watcher (for example a DNS client module written by |
521
|
|
|
|
|
|
|
somebody else even). Then you might want any outstanding requests to be |
522
|
|
|
|
|
|
|
handled, but you would not want to keep C from returning just |
523
|
|
|
|
|
|
|
because you happen to have this long-running UDP port watcher. |
524
|
|
|
|
|
|
|
|
525
|
|
|
|
|
|
|
In this case you can clear the keepalive status, which means that even |
526
|
|
|
|
|
|
|
though your watcher is active, it won't keep C from returning. |
527
|
|
|
|
|
|
|
|
528
|
|
|
|
|
|
|
The initial value for keepalive is true (enabled), and you can change it |
529
|
|
|
|
|
|
|
any time. |
530
|
|
|
|
|
|
|
|
531
|
|
|
|
|
|
|
Example: Register an I/O watcher for some UDP socket but do not keep the |
532
|
|
|
|
|
|
|
event loop from running just because of that watcher. |
533
|
|
|
|
|
|
|
|
534
|
|
|
|
|
|
|
my $udp_socket = ... |
535
|
|
|
|
|
|
|
my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
536
|
|
|
|
|
|
|
$udp_watcher->keepalive (0); |
537
|
|
|
|
|
|
|
|
538
|
|
|
|
|
|
|
=item $loop = $w->loop |
539
|
|
|
|
|
|
|
|
540
|
|
|
|
|
|
|
Return the loop that this watcher is attached to. |
541
|
|
|
|
|
|
|
|
542
|
|
|
|
|
|
|
=back |
543
|
|
|
|
|
|
|
|
544
|
|
|
|
|
|
|
|
545
|
|
|
|
|
|
|
=head1 WATCHER TYPES |
546
|
|
|
|
|
|
|
|
547
|
|
|
|
|
|
|
Each of the following subsections describes a single watcher type. |
548
|
|
|
|
|
|
|
|
549
|
|
|
|
|
|
|
=head3 I/O WATCHERS - is this file descriptor readable or writable? |
550
|
|
|
|
|
|
|
|
551
|
|
|
|
|
|
|
=over 4 |
552
|
|
|
|
|
|
|
|
553
|
|
|
|
|
|
|
=item $w = EV::io $fileno_or_fh, $eventmask, $callback |
554
|
|
|
|
|
|
|
|
555
|
|
|
|
|
|
|
=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
556
|
|
|
|
|
|
|
|
557
|
|
|
|
|
|
|
=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
558
|
|
|
|
|
|
|
|
559
|
|
|
|
|
|
|
=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
560
|
|
|
|
|
|
|
|
561
|
|
|
|
|
|
|
As long as the returned watcher object is alive, call the C<$callback> |
562
|
|
|
|
|
|
|
when at least one of events specified in C<$eventmask> occurs. |
563
|
|
|
|
|
|
|
|
564
|
|
|
|
|
|
|
The $eventmask can be one or more of these constants ORed together: |
565
|
|
|
|
|
|
|
|
566
|
|
|
|
|
|
|
EV::READ wait until read() wouldn't block anymore |
567
|
|
|
|
|
|
|
EV::WRITE wait until write() wouldn't block anymore |
568
|
|
|
|
|
|
|
|
569
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
570
|
|
|
|
|
|
|
|
571
|
|
|
|
|
|
|
=item $w->set ($fileno_or_fh, $eventmask) |
572
|
|
|
|
|
|
|
|
573
|
|
|
|
|
|
|
Reconfigures the watcher, see the constructor above for details. Can be |
574
|
|
|
|
|
|
|
called at any time. |
575
|
|
|
|
|
|
|
|
576
|
|
|
|
|
|
|
=item $current_fh = $w->fh |
577
|
|
|
|
|
|
|
|
578
|
|
|
|
|
|
|
=item $old_fh = $w->fh ($new_fh) |
579
|
|
|
|
|
|
|
|
580
|
|
|
|
|
|
|
Returns the previously set filehandle and optionally set a new one. |
581
|
|
|
|
|
|
|
|
582
|
|
|
|
|
|
|
=item $current_eventmask = $w->events |
583
|
|
|
|
|
|
|
|
584
|
|
|
|
|
|
|
=item $old_eventmask = $w->events ($new_eventmask) |
585
|
|
|
|
|
|
|
|
586
|
|
|
|
|
|
|
Returns the previously set event mask and optionally set a new one. |
587
|
|
|
|
|
|
|
|
588
|
|
|
|
|
|
|
=back |
589
|
|
|
|
|
|
|
|
590
|
|
|
|
|
|
|
|
591
|
|
|
|
|
|
|
=head3 TIMER WATCHERS - relative and optionally repeating timeouts |
592
|
|
|
|
|
|
|
|
593
|
|
|
|
|
|
|
=over 4 |
594
|
|
|
|
|
|
|
|
595
|
|
|
|
|
|
|
=item $w = EV::timer $after, $repeat, $callback |
596
|
|
|
|
|
|
|
|
597
|
|
|
|
|
|
|
=item $w = EV::timer_ns $after, $repeat, $callback |
598
|
|
|
|
|
|
|
|
599
|
|
|
|
|
|
|
=item $w = $loop->timer ($after, $repeat, $callback) |
600
|
|
|
|
|
|
|
|
601
|
|
|
|
|
|
|
=item $w = $loop->timer_ns ($after, $repeat, $callback) |
602
|
|
|
|
|
|
|
|
603
|
|
|
|
|
|
|
Calls the callback after C<$after> seconds (which may be fractional or |
604
|
|
|
|
|
|
|
negative). If C<$repeat> is non-zero, the timer will be restarted (with |
605
|
|
|
|
|
|
|
the $repeat value as $after) after the callback returns. |
606
|
|
|
|
|
|
|
|
607
|
|
|
|
|
|
|
This means that the callback would be called roughly after C<$after> |
608
|
|
|
|
|
|
|
seconds, and then every C<$repeat> seconds. The timer does his best not |
609
|
|
|
|
|
|
|
to drift, but it will not invoke the timer more often then once per event |
610
|
|
|
|
|
|
|
loop iteration, and might drift in other cases. If that isn't acceptable, |
611
|
|
|
|
|
|
|
look at EV::periodic, which can provide long-term stable timers. |
612
|
|
|
|
|
|
|
|
613
|
|
|
|
|
|
|
The timer is based on a monotonic clock, that is, if somebody is sitting |
614
|
|
|
|
|
|
|
in front of the machine while the timer is running and changes the system |
615
|
|
|
|
|
|
|
clock, the timer will nevertheless run (roughly) the same time. |
616
|
|
|
|
|
|
|
|
617
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
618
|
|
|
|
|
|
|
|
619
|
|
|
|
|
|
|
=item $w->set ($after, $repeat = 0) |
620
|
|
|
|
|
|
|
|
621
|
|
|
|
|
|
|
Reconfigures the watcher, see the constructor above for details. Can be called at |
622
|
|
|
|
|
|
|
any time. |
623
|
|
|
|
|
|
|
|
624
|
|
|
|
|
|
|
=item $w->again |
625
|
|
|
|
|
|
|
|
626
|
|
|
|
|
|
|
=item $w->again ($repeat) |
627
|
|
|
|
|
|
|
|
628
|
|
|
|
|
|
|
Similar to the C method, but has special semantics for repeating timers: |
629
|
|
|
|
|
|
|
|
630
|
|
|
|
|
|
|
If the timer is active and non-repeating, it will be stopped. |
631
|
|
|
|
|
|
|
|
632
|
|
|
|
|
|
|
If the timer is active and repeating, reset the timeout to occur |
633
|
|
|
|
|
|
|
C<$repeat> seconds after now. |
634
|
|
|
|
|
|
|
|
635
|
|
|
|
|
|
|
If the timer is inactive and repeating, start it using the repeat value. |
636
|
|
|
|
|
|
|
|
637
|
|
|
|
|
|
|
Otherwise do nothing. |
638
|
|
|
|
|
|
|
|
639
|
|
|
|
|
|
|
This behaviour is useful when you have a timeout for some IO |
640
|
|
|
|
|
|
|
operation. You create a timer object with the same value for C<$after> and |
641
|
|
|
|
|
|
|
C<$repeat>, and then, in the read/write watcher, run the C method |
642
|
|
|
|
|
|
|
on the timeout. |
643
|
|
|
|
|
|
|
|
644
|
|
|
|
|
|
|
If called with a C<$repeat> argument, then it uses this a timer repeat |
645
|
|
|
|
|
|
|
value. |
646
|
|
|
|
|
|
|
|
647
|
|
|
|
|
|
|
=item $after = $w->remaining |
648
|
|
|
|
|
|
|
|
649
|
|
|
|
|
|
|
Calculates and returns the remaining time till the timer will fire. |
650
|
|
|
|
|
|
|
|
651
|
|
|
|
|
|
|
=item $repeat = $w->repeat |
652
|
|
|
|
|
|
|
|
653
|
|
|
|
|
|
|
=item $old_repeat = $w->repeat ($new_repeat) |
654
|
|
|
|
|
|
|
|
655
|
|
|
|
|
|
|
Returns the current value of the repeat attribute and optionally sets a |
656
|
|
|
|
|
|
|
new one. Setting the new one will not restart the watcher - if the watcher |
657
|
|
|
|
|
|
|
is active, the new repeat value is used whenever it expires next. |
658
|
|
|
|
|
|
|
|
659
|
|
|
|
|
|
|
=back |
660
|
|
|
|
|
|
|
|
661
|
|
|
|
|
|
|
|
662
|
|
|
|
|
|
|
=head3 PERIODIC WATCHERS - to cron or not to cron? |
663
|
|
|
|
|
|
|
|
664
|
|
|
|
|
|
|
=over 4 |
665
|
|
|
|
|
|
|
|
666
|
|
|
|
|
|
|
=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
667
|
|
|
|
|
|
|
|
668
|
|
|
|
|
|
|
=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
669
|
|
|
|
|
|
|
|
670
|
|
|
|
|
|
|
=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
671
|
|
|
|
|
|
|
|
672
|
|
|
|
|
|
|
=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
673
|
|
|
|
|
|
|
|
674
|
|
|
|
|
|
|
Similar to EV::timer, but is not based on relative timeouts but on |
675
|
|
|
|
|
|
|
absolute times. Apart from creating "simple" timers that trigger "at" the |
676
|
|
|
|
|
|
|
specified time, it can also be used for non-drifting absolute timers and |
677
|
|
|
|
|
|
|
more complex, cron-like, setups that are not adversely affected by time |
678
|
|
|
|
|
|
|
jumps (i.e. when the system clock is changed by explicit date -s or other |
679
|
|
|
|
|
|
|
means such as ntpd). It is also the most complex watcher type in EV. |
680
|
|
|
|
|
|
|
|
681
|
|
|
|
|
|
|
It has three distinct "modes": |
682
|
|
|
|
|
|
|
|
683
|
|
|
|
|
|
|
=over 4 |
684
|
|
|
|
|
|
|
|
685
|
|
|
|
|
|
|
=item * absolute timer ($interval = $reschedule_cb = 0) |
686
|
|
|
|
|
|
|
|
687
|
|
|
|
|
|
|
This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
688
|
|
|
|
|
|
|
will not adjust when a time jump occurs, that is, if it is to be run |
689
|
|
|
|
|
|
|
at January 1st 2011 then it will run when the system time reaches or |
690
|
|
|
|
|
|
|
surpasses this time. |
691
|
|
|
|
|
|
|
|
692
|
|
|
|
|
|
|
=item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
693
|
|
|
|
|
|
|
|
694
|
|
|
|
|
|
|
In this mode the watcher will always be scheduled to time out at the |
695
|
|
|
|
|
|
|
next C<$at + N * $interval> time (for the lowest integer N) and then repeat, |
696
|
|
|
|
|
|
|
regardless of any time jumps. Note that, since C can be negative, the |
697
|
|
|
|
|
|
|
first trigger can happen before C<$at>. |
698
|
|
|
|
|
|
|
|
699
|
|
|
|
|
|
|
This can be used to create timers that do not drift with respect to system |
700
|
|
|
|
|
|
|
time: |
701
|
|
|
|
|
|
|
|
702
|
|
|
|
|
|
|
my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
703
|
|
|
|
|
|
|
|
704
|
|
|
|
|
|
|
That doesn't mean there will always be 3600 seconds in between triggers, |
705
|
|
|
|
|
|
|
but only that the the callback will be called when the system time shows a |
706
|
|
|
|
|
|
|
full hour (UTC). |
707
|
|
|
|
|
|
|
|
708
|
|
|
|
|
|
|
Another way to think about it (for the mathematically inclined) is that |
709
|
|
|
|
|
|
|
EV::periodic will try to run the callback in this mode at the next |
710
|
|
|
|
|
|
|
possible time where C<$time = $at (mod $interval)>, regardless of any time |
711
|
|
|
|
|
|
|
jumps. |
712
|
|
|
|
|
|
|
|
713
|
|
|
|
|
|
|
=item * manual reschedule mode ($reschedule_cb = coderef) |
714
|
|
|
|
|
|
|
|
715
|
|
|
|
|
|
|
In this mode $interval and $at are both being ignored. Instead, each |
716
|
|
|
|
|
|
|
time the periodic watcher gets scheduled, the reschedule callback |
717
|
|
|
|
|
|
|
($reschedule_cb) will be called with the watcher as first, and the current |
718
|
|
|
|
|
|
|
time as second argument. |
719
|
|
|
|
|
|
|
|
720
|
|
|
|
|
|
|
I
|
721
|
|
|
|
|
|
|
watcher, ever, and MUST NOT call any event loop functions or methods>. If |
722
|
|
|
|
|
|
|
you need to stop it, return 1e30 and stop it afterwards. You may create |
723
|
|
|
|
|
|
|
and start an C watcher for this task. |
724
|
|
|
|
|
|
|
|
725
|
|
|
|
|
|
|
It must return the next time to trigger, based on the passed time value |
726
|
|
|
|
|
|
|
(that is, the lowest time value larger than or equal to to the second |
727
|
|
|
|
|
|
|
argument). It will usually be called just before the callback will be |
728
|
|
|
|
|
|
|
triggered, but might be called at other times, too. |
729
|
|
|
|
|
|
|
|
730
|
|
|
|
|
|
|
This can be used to create very complex timers, such as a timer that |
731
|
|
|
|
|
|
|
triggers on each midnight, local time (actually one day after the last |
732
|
|
|
|
|
|
|
midnight, to keep the example simple): |
733
|
|
|
|
|
|
|
|
734
|
|
|
|
|
|
|
my $daily = EV::periodic 0, 0, sub { |
735
|
|
|
|
|
|
|
my ($w, $now) = @_; |
736
|
|
|
|
|
|
|
|
737
|
|
|
|
|
|
|
use Time::Local (); |
738
|
|
|
|
|
|
|
my (undef, undef, undef, $d, $m, $y) = localtime $now; |
739
|
|
|
|
|
|
|
Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y |
740
|
|
|
|
|
|
|
}, sub { |
741
|
|
|
|
|
|
|
print "it's midnight or likely shortly after, now\n"; |
742
|
|
|
|
|
|
|
}; |
743
|
|
|
|
|
|
|
|
744
|
|
|
|
|
|
|
=back |
745
|
|
|
|
|
|
|
|
746
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
747
|
|
|
|
|
|
|
|
748
|
|
|
|
|
|
|
=item $w->set ($at, $interval, $reschedule_cb) |
749
|
|
|
|
|
|
|
|
750
|
|
|
|
|
|
|
Reconfigures the watcher, see the constructor above for details. Can be called at |
751
|
|
|
|
|
|
|
any time. |
752
|
|
|
|
|
|
|
|
753
|
|
|
|
|
|
|
=item $w->again |
754
|
|
|
|
|
|
|
|
755
|
|
|
|
|
|
|
Simply stops and starts the watcher again. |
756
|
|
|
|
|
|
|
|
757
|
|
|
|
|
|
|
=item $time = $w->at |
758
|
|
|
|
|
|
|
|
759
|
|
|
|
|
|
|
Return the time that the watcher is expected to trigger next. |
760
|
|
|
|
|
|
|
|
761
|
|
|
|
|
|
|
=item $offset = $w->offset |
762
|
|
|
|
|
|
|
|
763
|
|
|
|
|
|
|
=item $old_offset = $w->offset ($new_offset) |
764
|
|
|
|
|
|
|
|
765
|
|
|
|
|
|
|
Returns the current value of the offset attribute and optionally sets a |
766
|
|
|
|
|
|
|
new one. Setting the new one will not restart the watcher - if the watcher |
767
|
|
|
|
|
|
|
is active, the new offset value is used whenever it expires next. |
768
|
|
|
|
|
|
|
|
769
|
|
|
|
|
|
|
=item $interval = $w->interval |
770
|
|
|
|
|
|
|
|
771
|
|
|
|
|
|
|
=item $old_interval = $w->interval ($new_interval) |
772
|
|
|
|
|
|
|
|
773
|
|
|
|
|
|
|
See above, for the interval attribute. |
774
|
|
|
|
|
|
|
|
775
|
|
|
|
|
|
|
=item $reschedule_cb = $w->reschedule_cb |
776
|
|
|
|
|
|
|
|
777
|
|
|
|
|
|
|
=item $old_reschedule_cb = $w->reschedule_cb ($new_reschedule_cb) |
778
|
|
|
|
|
|
|
|
779
|
|
|
|
|
|
|
See above, for the reschedule callback. |
780
|
|
|
|
|
|
|
|
781
|
|
|
|
|
|
|
=back |
782
|
|
|
|
|
|
|
|
783
|
|
|
|
|
|
|
|
784
|
|
|
|
|
|
|
=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
785
|
|
|
|
|
|
|
|
786
|
|
|
|
|
|
|
=over 4 |
787
|
|
|
|
|
|
|
|
788
|
|
|
|
|
|
|
=item $w = EV::signal $signal, $callback |
789
|
|
|
|
|
|
|
|
790
|
|
|
|
|
|
|
=item $w = EV::signal_ns $signal, $callback |
791
|
|
|
|
|
|
|
|
792
|
|
|
|
|
|
|
=item $w = $loop->signal ($signal, $callback) |
793
|
|
|
|
|
|
|
|
794
|
|
|
|
|
|
|
=item $w = $loop->signal_ns ($signal, $callback) |
795
|
|
|
|
|
|
|
|
796
|
|
|
|
|
|
|
Call the callback when $signal is received (the signal can be specified by |
797
|
|
|
|
|
|
|
number or by name, just as with C or C<%SIG>). |
798
|
|
|
|
|
|
|
|
799
|
|
|
|
|
|
|
Only one event loop can grab a given signal - attempting to grab the same |
800
|
|
|
|
|
|
|
signal from two EV loops will crash the program immediately or cause data |
801
|
|
|
|
|
|
|
corruption. |
802
|
|
|
|
|
|
|
|
803
|
|
|
|
|
|
|
EV will grab the signal for the process (the kernel only allows one |
804
|
|
|
|
|
|
|
component to receive a signal at a time) when you start a signal watcher, |
805
|
|
|
|
|
|
|
and removes it again when you stop it. Perl does the same when you |
806
|
|
|
|
|
|
|
add/remove callbacks to C<%SIG>, so watch out. |
807
|
|
|
|
|
|
|
|
808
|
|
|
|
|
|
|
You can have as many signal watchers per signal as you want. |
809
|
|
|
|
|
|
|
|
810
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
811
|
|
|
|
|
|
|
|
812
|
|
|
|
|
|
|
=item $w->set ($signal) |
813
|
|
|
|
|
|
|
|
814
|
|
|
|
|
|
|
Reconfigures the watcher, see the constructor above for details. Can be |
815
|
|
|
|
|
|
|
called at any time. |
816
|
|
|
|
|
|
|
|
817
|
|
|
|
|
|
|
=item $current_signum = $w->signal |
818
|
|
|
|
|
|
|
|
819
|
|
|
|
|
|
|
=item $old_signum = $w->signal ($new_signal) |
820
|
|
|
|
|
|
|
|
821
|
|
|
|
|
|
|
Returns the previously set signal (always as a number not name) and |
822
|
|
|
|
|
|
|
optionally set a new one. |
823
|
|
|
|
|
|
|
|
824
|
|
|
|
|
|
|
=back |
825
|
|
|
|
|
|
|
|
826
|
|
|
|
|
|
|
|
827
|
|
|
|
|
|
|
=head3 CHILD WATCHERS - watch out for process status changes |
828
|
|
|
|
|
|
|
|
829
|
|
|
|
|
|
|
=over 4 |
830
|
|
|
|
|
|
|
|
831
|
|
|
|
|
|
|
=item $w = EV::child $pid, $trace, $callback |
832
|
|
|
|
|
|
|
|
833
|
|
|
|
|
|
|
=item $w = EV::child_ns $pid, $trace, $callback |
834
|
|
|
|
|
|
|
|
835
|
|
|
|
|
|
|
=item $w = $loop->child ($pid, $trace, $callback) |
836
|
|
|
|
|
|
|
|
837
|
|
|
|
|
|
|
=item $w = $loop->child_ns ($pid, $trace, $callback) |
838
|
|
|
|
|
|
|
|
839
|
|
|
|
|
|
|
Call the callback when a status change for pid C<$pid> (or any pid |
840
|
|
|
|
|
|
|
if C<$pid> is 0) has been received (a status change happens when the |
841
|
|
|
|
|
|
|
process terminates or is killed, or, when trace is true, additionally when |
842
|
|
|
|
|
|
|
it is stopped or continued). More precisely: when the process receives |
843
|
|
|
|
|
|
|
a C, EV will fetch the outstanding exit/wait status for all |
844
|
|
|
|
|
|
|
changed/zombie children and call the callback. |
845
|
|
|
|
|
|
|
|
846
|
|
|
|
|
|
|
It is valid (and fully supported) to install a child watcher after a child |
847
|
|
|
|
|
|
|
has exited but before the event loop has started its next iteration (for |
848
|
|
|
|
|
|
|
example, first you C, then the new child process might exit, and |
849
|
|
|
|
|
|
|
only then do you install a child watcher in the parent for the new pid). |
850
|
|
|
|
|
|
|
|
851
|
|
|
|
|
|
|
You can access both exit (or tracing) status and pid by using the |
852
|
|
|
|
|
|
|
C and C methods on the watcher object. |
853
|
|
|
|
|
|
|
|
854
|
|
|
|
|
|
|
You can have as many pid watchers per pid as you want, they will all be |
855
|
|
|
|
|
|
|
called. |
856
|
|
|
|
|
|
|
|
857
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
858
|
|
|
|
|
|
|
|
859
|
|
|
|
|
|
|
=item $w->set ($pid, $trace) |
860
|
|
|
|
|
|
|
|
861
|
|
|
|
|
|
|
Reconfigures the watcher, see the constructor above for details. Can be called at |
862
|
|
|
|
|
|
|
any time. |
863
|
|
|
|
|
|
|
|
864
|
|
|
|
|
|
|
=item $current_pid = $w->pid |
865
|
|
|
|
|
|
|
|
866
|
|
|
|
|
|
|
Returns the previously set process id and optionally set a new one. |
867
|
|
|
|
|
|
|
|
868
|
|
|
|
|
|
|
=item $exit_status = $w->rstatus |
869
|
|
|
|
|
|
|
|
870
|
|
|
|
|
|
|
Return the exit/wait status (as returned by waitpid, see the waitpid entry |
871
|
|
|
|
|
|
|
in perlfunc). |
872
|
|
|
|
|
|
|
|
873
|
|
|
|
|
|
|
=item $pid = $w->rpid |
874
|
|
|
|
|
|
|
|
875
|
|
|
|
|
|
|
Return the pid of the awaited child (useful when you have installed a |
876
|
|
|
|
|
|
|
watcher for all pids). |
877
|
|
|
|
|
|
|
|
878
|
|
|
|
|
|
|
=back |
879
|
|
|
|
|
|
|
|
880
|
|
|
|
|
|
|
|
881
|
|
|
|
|
|
|
=head3 STAT WATCHERS - did the file attributes just change? |
882
|
|
|
|
|
|
|
|
883
|
|
|
|
|
|
|
=over 4 |
884
|
|
|
|
|
|
|
|
885
|
|
|
|
|
|
|
=item $w = EV::stat $path, $interval, $callback |
886
|
|
|
|
|
|
|
|
887
|
|
|
|
|
|
|
=item $w = EV::stat_ns $path, $interval, $callback |
888
|
|
|
|
|
|
|
|
889
|
|
|
|
|
|
|
=item $w = $loop->stat ($path, $interval, $callback) |
890
|
|
|
|
|
|
|
|
891
|
|
|
|
|
|
|
=item $w = $loop->stat_ns ($path, $interval, $callback) |
892
|
|
|
|
|
|
|
|
893
|
|
|
|
|
|
|
Call the callback when a file status change has been detected on |
894
|
|
|
|
|
|
|
C<$path>. The C<$path> does not need to exist, changing from "path exists" |
895
|
|
|
|
|
|
|
to "path does not exist" is a status change like any other. |
896
|
|
|
|
|
|
|
|
897
|
|
|
|
|
|
|
The C<$interval> is a recommended polling interval for systems where |
898
|
|
|
|
|
|
|
OS-supported change notifications don't exist or are not supported. If |
899
|
|
|
|
|
|
|
you use C<0> then an unspecified default is used (which is highly |
900
|
|
|
|
|
|
|
recommended!), which is to be expected to be around five seconds usually. |
901
|
|
|
|
|
|
|
|
902
|
|
|
|
|
|
|
This watcher type is not meant for massive numbers of stat watchers, |
903
|
|
|
|
|
|
|
as even with OS-supported change notifications, this can be |
904
|
|
|
|
|
|
|
resource-intensive. |
905
|
|
|
|
|
|
|
|
906
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
907
|
|
|
|
|
|
|
|
908
|
|
|
|
|
|
|
=item ... = $w->stat |
909
|
|
|
|
|
|
|
|
910
|
|
|
|
|
|
|
This call is very similar to the perl C built-in: It stats (using |
911
|
|
|
|
|
|
|
C) the path specified in the watcher and sets perls stat cache (as |
912
|
|
|
|
|
|
|
well as EV's idea of the current stat values) to the values found. |
913
|
|
|
|
|
|
|
|
914
|
|
|
|
|
|
|
In scalar context, a boolean is return indicating success or failure of |
915
|
|
|
|
|
|
|
the stat. In list context, the same 13-value list as with stat is returned |
916
|
|
|
|
|
|
|
(except that the blksize and blocks fields are not reliable). |
917
|
|
|
|
|
|
|
|
918
|
|
|
|
|
|
|
In the case of an error, errno is set to C (regardless of the |
919
|
|
|
|
|
|
|
actual error value) and the C value is forced to zero (if the stat |
920
|
|
|
|
|
|
|
was successful then nlink is guaranteed to be non-zero). |
921
|
|
|
|
|
|
|
|
922
|
|
|
|
|
|
|
See also the next two entries for more info. |
923
|
|
|
|
|
|
|
|
924
|
|
|
|
|
|
|
=item ... = $w->attr |
925
|
|
|
|
|
|
|
|
926
|
|
|
|
|
|
|
Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
927
|
|
|
|
|
|
|
the values most recently detected by EV. See the next entry for more info. |
928
|
|
|
|
|
|
|
|
929
|
|
|
|
|
|
|
=item ... = $w->prev |
930
|
|
|
|
|
|
|
|
931
|
|
|
|
|
|
|
Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
932
|
|
|
|
|
|
|
the previous set of values, before the change. |
933
|
|
|
|
|
|
|
|
934
|
|
|
|
|
|
|
That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
935
|
|
|
|
|
|
|
to the values found I a change was detected, while C<< $w->attr >> |
936
|
|
|
|
|
|
|
returns the values found leading to the change detection. The difference (if any) |
937
|
|
|
|
|
|
|
between C and C is what triggered the callback. |
938
|
|
|
|
|
|
|
|
939
|
|
|
|
|
|
|
If you did something to the filesystem object and do not want to trigger |
940
|
|
|
|
|
|
|
yet another change, you can call C to update EV's idea of what the |
941
|
|
|
|
|
|
|
current attributes are. |
942
|
|
|
|
|
|
|
|
943
|
|
|
|
|
|
|
=item $w->set ($path, $interval) |
944
|
|
|
|
|
|
|
|
945
|
|
|
|
|
|
|
Reconfigures the watcher, see the constructor above for details. Can be |
946
|
|
|
|
|
|
|
called at any time. |
947
|
|
|
|
|
|
|
|
948
|
|
|
|
|
|
|
=item $current_path = $w->path |
949
|
|
|
|
|
|
|
|
950
|
|
|
|
|
|
|
=item $old_path = $w->path ($new_path) |
951
|
|
|
|
|
|
|
|
952
|
|
|
|
|
|
|
Returns the previously set path and optionally set a new one. |
953
|
|
|
|
|
|
|
|
954
|
|
|
|
|
|
|
=item $current_interval = $w->interval |
955
|
|
|
|
|
|
|
|
956
|
|
|
|
|
|
|
=item $old_interval = $w->interval ($new_interval) |
957
|
|
|
|
|
|
|
|
958
|
|
|
|
|
|
|
Returns the previously set interval and optionally set a new one. Can be |
959
|
|
|
|
|
|
|
used to query the actual interval used. |
960
|
|
|
|
|
|
|
|
961
|
|
|
|
|
|
|
=back |
962
|
|
|
|
|
|
|
|
963
|
|
|
|
|
|
|
|
964
|
|
|
|
|
|
|
=head3 IDLE WATCHERS - when you've got nothing better to do... |
965
|
|
|
|
|
|
|
|
966
|
|
|
|
|
|
|
=over 4 |
967
|
|
|
|
|
|
|
|
968
|
|
|
|
|
|
|
=item $w = EV::idle $callback |
969
|
|
|
|
|
|
|
|
970
|
|
|
|
|
|
|
=item $w = EV::idle_ns $callback |
971
|
|
|
|
|
|
|
|
972
|
|
|
|
|
|
|
=item $w = $loop->idle ($callback) |
973
|
|
|
|
|
|
|
|
974
|
|
|
|
|
|
|
=item $w = $loop->idle_ns ($callback) |
975
|
|
|
|
|
|
|
|
976
|
|
|
|
|
|
|
Call the callback when there are no other pending watchers of the same or |
977
|
|
|
|
|
|
|
higher priority (excluding check, prepare and other idle watchers of the |
978
|
|
|
|
|
|
|
same or lower priority, of course). They are called idle watchers because |
979
|
|
|
|
|
|
|
when the watcher is the highest priority pending event in the process, the |
980
|
|
|
|
|
|
|
process is considered to be idle at that priority. |
981
|
|
|
|
|
|
|
|
982
|
|
|
|
|
|
|
If you want a watcher that is only ever called when I other events are |
983
|
|
|
|
|
|
|
outstanding you have to set the priority to C. |
984
|
|
|
|
|
|
|
|
985
|
|
|
|
|
|
|
The process will not block as long as any idle watchers are active, and |
986
|
|
|
|
|
|
|
they will be called repeatedly until stopped. |
987
|
|
|
|
|
|
|
|
988
|
|
|
|
|
|
|
For example, if you have idle watchers at priority C<0> and C<1>, and |
989
|
|
|
|
|
|
|
an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
990
|
|
|
|
|
|
|
and the I/O watcher will always run when ready. Only when the idle watcher |
991
|
|
|
|
|
|
|
at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
992
|
|
|
|
|
|
|
pending with the C<0>-priority idle watcher be invoked. |
993
|
|
|
|
|
|
|
|
994
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
995
|
|
|
|
|
|
|
|
996
|
|
|
|
|
|
|
=back |
997
|
|
|
|
|
|
|
|
998
|
|
|
|
|
|
|
|
999
|
|
|
|
|
|
|
=head3 PREPARE WATCHERS - customise your event loop! |
1000
|
|
|
|
|
|
|
|
1001
|
|
|
|
|
|
|
=over 4 |
1002
|
|
|
|
|
|
|
|
1003
|
|
|
|
|
|
|
=item $w = EV::prepare $callback |
1004
|
|
|
|
|
|
|
|
1005
|
|
|
|
|
|
|
=item $w = EV::prepare_ns $callback |
1006
|
|
|
|
|
|
|
|
1007
|
|
|
|
|
|
|
=item $w = $loop->prepare ($callback) |
1008
|
|
|
|
|
|
|
|
1009
|
|
|
|
|
|
|
=item $w = $loop->prepare_ns ($callback) |
1010
|
|
|
|
|
|
|
|
1011
|
|
|
|
|
|
|
Call the callback just before the process would block. You can still |
1012
|
|
|
|
|
|
|
create/modify any watchers at this point. |
1013
|
|
|
|
|
|
|
|
1014
|
|
|
|
|
|
|
See the EV::check watcher, below, for explanations and an example. |
1015
|
|
|
|
|
|
|
|
1016
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
1017
|
|
|
|
|
|
|
|
1018
|
|
|
|
|
|
|
=back |
1019
|
|
|
|
|
|
|
|
1020
|
|
|
|
|
|
|
|
1021
|
|
|
|
|
|
|
=head3 CHECK WATCHERS - customise your event loop even more! |
1022
|
|
|
|
|
|
|
|
1023
|
|
|
|
|
|
|
=over 4 |
1024
|
|
|
|
|
|
|
|
1025
|
|
|
|
|
|
|
=item $w = EV::check $callback |
1026
|
|
|
|
|
|
|
|
1027
|
|
|
|
|
|
|
=item $w = EV::check_ns $callback |
1028
|
|
|
|
|
|
|
|
1029
|
|
|
|
|
|
|
=item $w = $loop->check ($callback) |
1030
|
|
|
|
|
|
|
|
1031
|
|
|
|
|
|
|
=item $w = $loop->check_ns ($callback) |
1032
|
|
|
|
|
|
|
|
1033
|
|
|
|
|
|
|
Call the callback just after the process wakes up again (after it has |
1034
|
|
|
|
|
|
|
gathered events), but before any other callbacks have been invoked. |
1035
|
|
|
|
|
|
|
|
1036
|
|
|
|
|
|
|
This can be used to integrate other event-based software into the EV |
1037
|
|
|
|
|
|
|
mainloop: You register a prepare callback and in there, you create io and |
1038
|
|
|
|
|
|
|
timer watchers as required by the other software. Here is a real-world |
1039
|
|
|
|
|
|
|
example of integrating Net::SNMP (with some details left out): |
1040
|
|
|
|
|
|
|
|
1041
|
|
|
|
|
|
|
our @snmp_watcher; |
1042
|
|
|
|
|
|
|
|
1043
|
|
|
|
|
|
|
our $snmp_prepare = EV::prepare sub { |
1044
|
|
|
|
|
|
|
# do nothing unless active |
1045
|
|
|
|
|
|
|
$dispatcher->{_event_queue_h} |
1046
|
|
|
|
|
|
|
or return; |
1047
|
|
|
|
|
|
|
|
1048
|
|
|
|
|
|
|
# make the dispatcher handle any outstanding stuff |
1049
|
|
|
|
|
|
|
... not shown |
1050
|
|
|
|
|
|
|
|
1051
|
|
|
|
|
|
|
# create an I/O watcher for each and every socket |
1052
|
|
|
|
|
|
|
@snmp_watcher = ( |
1053
|
|
|
|
|
|
|
(map { EV::io $_, EV::READ, sub { } } |
1054
|
|
|
|
|
|
|
keys %{ $dispatcher->{_descriptors} }), |
1055
|
|
|
|
|
|
|
|
1056
|
|
|
|
|
|
|
EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
1057
|
|
|
|
|
|
|
? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
1058
|
|
|
|
|
|
|
0, sub { }, |
1059
|
|
|
|
|
|
|
); |
1060
|
|
|
|
|
|
|
}; |
1061
|
|
|
|
|
|
|
|
1062
|
|
|
|
|
|
|
The callbacks are irrelevant (and are not even being called), the |
1063
|
|
|
|
|
|
|
only purpose of those watchers is to wake up the process as soon as |
1064
|
|
|
|
|
|
|
one of those events occurs (socket readable, or timer timed out). The |
1065
|
|
|
|
|
|
|
corresponding EV::check watcher will then clean up: |
1066
|
|
|
|
|
|
|
|
1067
|
|
|
|
|
|
|
our $snmp_check = EV::check sub { |
1068
|
|
|
|
|
|
|
# destroy all watchers |
1069
|
|
|
|
|
|
|
@snmp_watcher = (); |
1070
|
|
|
|
|
|
|
|
1071
|
|
|
|
|
|
|
# make the dispatcher handle any new stuff |
1072
|
|
|
|
|
|
|
... not shown |
1073
|
|
|
|
|
|
|
}; |
1074
|
|
|
|
|
|
|
|
1075
|
|
|
|
|
|
|
The callbacks of the created watchers will not be called as the watchers |
1076
|
|
|
|
|
|
|
are destroyed before this can happen (remember EV::check gets called |
1077
|
|
|
|
|
|
|
first). |
1078
|
|
|
|
|
|
|
|
1079
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
1080
|
|
|
|
|
|
|
|
1081
|
|
|
|
|
|
|
=item EV::CHECK constant issues |
1082
|
|
|
|
|
|
|
|
1083
|
|
|
|
|
|
|
Like all other watcher types, there is a bitmask constant for use in |
1084
|
|
|
|
|
|
|
C<$revents> and other places. The C is special as it has |
1085
|
|
|
|
|
|
|
the same name as the C sub called by Perl. This doesn't cause |
1086
|
|
|
|
|
|
|
big issues on newer perls (beginning with 5.8.9), but it means thatthe |
1087
|
|
|
|
|
|
|
constant must be I, i.e. runtime calls will not work. That means |
1088
|
|
|
|
|
|
|
that as long as you always C |
1089
|
|
|
|
|
|
|
safe side. |
1090
|
|
|
|
|
|
|
|
1091
|
|
|
|
|
|
|
=back |
1092
|
|
|
|
|
|
|
|
1093
|
|
|
|
|
|
|
|
1094
|
|
|
|
|
|
|
=head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
1095
|
|
|
|
|
|
|
|
1096
|
|
|
|
|
|
|
Fork watchers are called when a C was detected. The invocation |
1097
|
|
|
|
|
|
|
is done before the event loop blocks next and before C watchers |
1098
|
|
|
|
|
|
|
are being called, and only in the child after the fork. |
1099
|
|
|
|
|
|
|
|
1100
|
|
|
|
|
|
|
=over 4 |
1101
|
|
|
|
|
|
|
|
1102
|
|
|
|
|
|
|
=item $w = EV::fork $callback |
1103
|
|
|
|
|
|
|
|
1104
|
|
|
|
|
|
|
=item $w = EV::fork_ns $callback |
1105
|
|
|
|
|
|
|
|
1106
|
|
|
|
|
|
|
=item $w = $loop->fork ($callback) |
1107
|
|
|
|
|
|
|
|
1108
|
|
|
|
|
|
|
=item $w = $loop->fork_ns ($callback) |
1109
|
|
|
|
|
|
|
|
1110
|
|
|
|
|
|
|
Call the callback before the event loop is resumed in the child process |
1111
|
|
|
|
|
|
|
after a fork. |
1112
|
|
|
|
|
|
|
|
1113
|
|
|
|
|
|
|
The C variant doesn't start (activate) the newly created watcher. |
1114
|
|
|
|
|
|
|
|
1115
|
|
|
|
|
|
|
=back |
1116
|
|
|
|
|
|
|
|
1117
|
|
|
|
|
|
|
|
1118
|
|
|
|
|
|
|
=head3 EMBED WATCHERS - when one backend isn't enough... |
1119
|
|
|
|
|
|
|
|
1120
|
|
|
|
|
|
|
This is a rather advanced watcher type that lets you embed one event loop |
1121
|
|
|
|
|
|
|
into another (currently only IO events are supported in the embedded |
1122
|
|
|
|
|
|
|
loop, other types of watchers might be handled in a delayed or incorrect |
1123
|
|
|
|
|
|
|
fashion and must not be used). |
1124
|
|
|
|
|
|
|
|
1125
|
|
|
|
|
|
|
See the libev documentation at |
1126
|
|
|
|
|
|
|
L |
1127
|
|
|
|
|
|
|
(locally installed as F) for more details. |
1128
|
|
|
|
|
|
|
|
1129
|
|
|
|
|
|
|
In short, this watcher is most useful on BSD systems without working |
1130
|
|
|
|
|
|
|
kqueue to still be able to handle a large number of sockets: |
1131
|
|
|
|
|
|
|
|
1132
|
|
|
|
|
|
|
my $socket_loop; |
1133
|
|
|
|
|
|
|
|
1134
|
|
|
|
|
|
|
# check wether we use SELECT or POLL _and_ KQUEUE is supported |
1135
|
|
|
|
|
|
|
if ( |
1136
|
|
|
|
|
|
|
(EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
1137
|
|
|
|
|
|
|
&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
1138
|
|
|
|
|
|
|
) { |
1139
|
|
|
|
|
|
|
# use kqueue for sockets |
1140
|
|
|
|
|
|
|
$socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
1141
|
|
|
|
|
|
|
} |
1142
|
|
|
|
|
|
|
|
1143
|
|
|
|
|
|
|
# use the default loop otherwise |
1144
|
|
|
|
|
|
|
$socket_loop ||= EV::default_loop; |
1145
|
|
|
|
|
|
|
|
1146
|
|
|
|
|
|
|
=over 4 |
1147
|
|
|
|
|
|
|
|
1148
|
|
|
|
|
|
|
=item $w = EV::embed $otherloop[, $callback] |
1149
|
|
|
|
|
|
|
|
1150
|
|
|
|
|
|
|
=item $w = EV::embed_ns $otherloop[, $callback] |
1151
|
|
|
|
|
|
|
|
1152
|
|
|
|
|
|
|
=item $w = $loop->embed ($otherloop[, $callback]) |
1153
|
|
|
|
|
|
|
|
1154
|
|
|
|
|
|
|
=item $w = $loop->embed_ns ($otherloop[, $callback]) |
1155
|
|
|
|
|
|
|
|
1156
|
|
|
|
|
|
|
Call the callback when the embedded event loop (C<$otherloop>) has any |
1157
|
|
|
|
|
|
|
I/O activity. The C<$callback> is optional: if it is missing, then the |
1158
|
|
|
|
|
|
|
embedded event loop will be managed automatically (which is recommended), |
1159
|
|
|
|
|
|
|
otherwise you have to invoke C yourself. |
1160
|
|
|
|
|
|
|
|
1161
|
|
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|
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|
|
The C variant doesn't start (activate) the newly created watcher. |
1162
|
|
|
|
|
|
|
|
1163
|
|
|
|
|
|
|
=back |
1164
|
|
|
|
|
|
|
|
1165
|
|
|
|
|
|
|
=head3 ASYNC WATCHERS - how to wake up another event loop |
1166
|
|
|
|
|
|
|
|
1167
|
|
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|
|
|
|
Async watchers are provided by EV, but have little use in perl directly, |
1168
|
|
|
|
|
|
|
as perl neither supports threads running in parallel nor direct access to |
1169
|
|
|
|
|
|
|
signal handlers or other contexts where they could be of value. |
1170
|
|
|
|
|
|
|
|
1171
|
|
|
|
|
|
|
It is, however, possible to use them from the XS level. |
1172
|
|
|
|
|
|
|
|
1173
|
|
|
|
|
|
|
Please see the libev documentation for further details. |
1174
|
|
|
|
|
|
|
|
1175
|
|
|
|
|
|
|
=over 4 |
1176
|
|
|
|
|
|
|
|
1177
|
|
|
|
|
|
|
=item $w = EV::async $callback |
1178
|
|
|
|
|
|
|
|
1179
|
|
|
|
|
|
|
=item $w = EV::async_ns $callback |
1180
|
|
|
|
|
|
|
|
1181
|
|
|
|
|
|
|
=item $w = $loop->async ($callback) |
1182
|
|
|
|
|
|
|
|
1183
|
|
|
|
|
|
|
=item $w = $loop->async_ns ($callback) |
1184
|
|
|
|
|
|
|
|
1185
|
|
|
|
|
|
|
=item $w->send |
1186
|
|
|
|
|
|
|
|
1187
|
|
|
|
|
|
|
=item $bool = $w->async_pending |
1188
|
|
|
|
|
|
|
|
1189
|
|
|
|
|
|
|
=back |
1190
|
|
|
|
|
|
|
|
1191
|
|
|
|
|
|
|
=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away |
1192
|
|
|
|
|
|
|
|
1193
|
|
|
|
|
|
|
Cleanup watchers are not supported on the Perl level, they can only be |
1194
|
|
|
|
|
|
|
used via XS currently. |
1195
|
|
|
|
|
|
|
|
1196
|
|
|
|
|
|
|
|
1197
|
|
|
|
|
|
|
=head1 PERL SIGNALS |
1198
|
|
|
|
|
|
|
|
1199
|
|
|
|
|
|
|
While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
1200
|
|
|
|
|
|
|
with EV is as the same as any other C library: Perl-signals will only be |
1201
|
|
|
|
|
|
|
handled when Perl runs, which means your signal handler might be invoked |
1202
|
|
|
|
|
|
|
only the next time an event callback is invoked. |
1203
|
|
|
|
|
|
|
|
1204
|
|
|
|
|
|
|
The solution is to use EV signal watchers (see C), which will |
1205
|
|
|
|
|
|
|
ensure proper operations with regards to other event watchers. |
1206
|
|
|
|
|
|
|
|
1207
|
|
|
|
|
|
|
If you cannot do this for whatever reason, you can also force a watcher |
1208
|
|
|
|
|
|
|
to be called on every event loop iteration by installing a C |
1209
|
|
|
|
|
|
|
watcher: |
1210
|
|
|
|
|
|
|
|
1211
|
|
|
|
|
|
|
my $async_check = EV::check sub { }; |
1212
|
|
|
|
|
|
|
|
1213
|
|
|
|
|
|
|
This ensures that perl gets into control for a short time to handle any |
1214
|
|
|
|
|
|
|
pending signals, and also ensures (slightly) slower overall operation. |
1215
|
|
|
|
|
|
|
|
1216
|
|
|
|
|
|
|
=head1 ITHREADS |
1217
|
|
|
|
|
|
|
|
1218
|
|
|
|
|
|
|
Ithreads are not supported by this module in any way. Perl pseudo-threads |
1219
|
|
|
|
|
|
|
is evil stuff and must die. Real threads as provided by Coro are fully |
1220
|
|
|
|
|
|
|
supported (and enhanced support is available via L). |
1221
|
|
|
|
|
|
|
|
1222
|
|
|
|
|
|
|
=head1 FORK |
1223
|
|
|
|
|
|
|
|
1224
|
|
|
|
|
|
|
Most of the "improved" event delivering mechanisms of modern operating |
1225
|
|
|
|
|
|
|
systems have quite a few problems with fork(2) (to put it bluntly: it is |
1226
|
|
|
|
|
|
|
not supported and usually destructive). Libev makes it possible to work |
1227
|
|
|
|
|
|
|
around this by having a function that recreates the kernel state after |
1228
|
|
|
|
|
|
|
fork in the child. |
1229
|
|
|
|
|
|
|
|
1230
|
|
|
|
|
|
|
On non-win32 platforms, this module requires the pthread_atfork |
1231
|
|
|
|
|
|
|
functionality to do this automatically for you. This function is quite |
1232
|
|
|
|
|
|
|
buggy on most BSDs, though, so YMMV. The overhead for this is quite |
1233
|
|
|
|
|
|
|
negligible, because everything the function currently does is set a flag |
1234
|
|
|
|
|
|
|
that is checked only when the event loop gets used the next time, so when |
1235
|
|
|
|
|
|
|
you do fork but not use EV, the overhead is minimal. |
1236
|
|
|
|
|
|
|
|
1237
|
|
|
|
|
|
|
On win32, there is no notion of fork so all this doesn't apply, of course. |
1238
|
|
|
|
|
|
|
|
1239
|
|
|
|
|
|
|
=cut |
1240
|
|
|
|
|
|
|
|
1241
|
|
|
|
|
|
|
our $DIED = sub { |
1242
|
|
|
|
|
|
|
warn "EV: error in callback (ignoring): $@"; |
1243
|
|
|
|
|
|
|
}; |
1244
|
|
|
|
|
|
|
|
1245
|
|
|
|
|
|
|
default_loop |
1246
|
|
|
|
|
|
|
or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
1247
|
|
|
|
|
|
|
|
1248
|
|
|
|
|
|
|
1; |
1249
|
|
|
|
|
|
|
|
1250
|
|
|
|
|
|
|
=head1 SEE ALSO |
1251
|
|
|
|
|
|
|
|
1252
|
|
|
|
|
|
|
L - MakeMaker interface to XS API, L |
1253
|
|
|
|
|
|
|
(asynchronous DNS), L (makes Glib/Gtk2 use EV as event |
1254
|
|
|
|
|
|
|
loop), L (embed Glib into EV), L (efficient thread |
1255
|
|
|
|
|
|
|
integration), L (asynchronous SNMP), L for |
1256
|
|
|
|
|
|
|
event-loop agnostic and portable event driven programming. |
1257
|
|
|
|
|
|
|
|
1258
|
|
|
|
|
|
|
=head1 AUTHOR |
1259
|
|
|
|
|
|
|
|
1260
|
|
|
|
|
|
|
Marc Lehmann |
1261
|
|
|
|
|
|
|
http://home.schmorp.de/ |
1262
|
|
|
|
|
|
|
|
1263
|
|
|
|
|
|
|
=cut |
1264
|
|
|
|
|
|
|
|