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1.1 |
=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: ", <STDIN>; |
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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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1.2 |
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1.127 |
=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<AnyEvent> instead, |
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specifically the simplified API described in L<AE>. |
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When used with EV as backend, the L<AE> API is as fast as the native L<EV> |
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API, but your programs/modules will still run with many other event loops. |
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1.1 |
=head1 DESCRIPTION |
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This module provides an interface to libev |
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(L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
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below is comprehensive, one might also consult the documentation of |
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libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or |
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F<perldoc EV::libev>) 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<LIBEV_FLAGS>, 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<AnyEvent> 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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=head2 PORTING FROM EV 3.X to 4.X |
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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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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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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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The loop object methods corresponding to the functions above have been |
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similarly renamed. |
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=head2 MODULE EXPORTS |
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This module does not export any symbols. |
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1.1 |
=cut |
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package EV; |
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use common::sense; |
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BEGIN { |
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our $VERSION = 4.29; |
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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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@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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=head1 EVENT LOOPS |
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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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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 |
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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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For specific programs you can create additional event loops dynamically. |
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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<embed> a kqueue loop into the default loop: running the default loop |
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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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=over 4 |
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=item $loop = new EV::Loop [$flags] |
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Create a new event loop as per the specified flags. Please refer to |
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the C<ev_loop_new ()> function description in the libev documentation |
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(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>, |
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or locally-installed as F<EV::libev> manpage) for more info. |
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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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If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK> |
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is recommended, as only the default event loop is protected by this |
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module. If you I<are> embedding this loop in the default loop, this is not |
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necessary, as C<EV::embed> automatically does the right thing on fork. |
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1.73 |
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=item $loop->loop_fork |
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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<EV::FLAG_FORKCHECK> which calls |
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this function automatically, at some performance loss (refer to the libev |
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documentation). |
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=item $loop->verify |
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Calls C<ev_verify> to make internal consistency checks (for debugging |
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1.99 |
libev) and abort the program if any data structures were found to be |
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corrupted. |
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=item $loop = EV::default_loop [$flags] |
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Return the default loop (which is a singleton object). Since this module |
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already creates the default loop with default flags, specifying flags here |
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will not have any effect unless you destroy the default loop first, which |
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isn't supported. So in short: don't do it, and if you break it, you get to |
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keep the pieces. |
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1.73 |
=back |
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1.8 |
=head1 BASIC INTERFACE |
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=over 4 |
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1.8 |
=item $EV::DIED |
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Must contain a reference to a function that is called when a callback |
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1.67 |
throws an exception (with $@ containing the error). The default prints an |
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1.8 |
informative message and continues. |
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If this callback throws an exception it will be silently ignored. |
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=item $flags = EV::supported_backends |
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=item $flags = EV::recommended_backends |
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=item $flags = EV::embeddable_backends |
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Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this |
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instance of EV, the set of recommended backends (supposed to be good) for |
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this platform and the set of embeddable backends (see EMBED WATCHERS). |
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1.80 |
=item EV::sleep $seconds |
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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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1.20 |
usually faster then calling EV::time. |
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1.114 |
=item EV::now_update |
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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<EV::now> in the progress. This is a costly operation and |
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1.155 |
is usually done automatically within C<EV::run>. |
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1.114 |
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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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=item $loop->suspend |
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=item EV::resume |
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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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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<suspend> |
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in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling |
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C<resume> directly afterwards to resume timer processing. |
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Effectively, all C<timer> watchers will be delayed by the time spend |
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between C<suspend> and C<resume>, and all C<periodic> 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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After calling C<suspend> you B<must not> call I<any> function on the given |
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loop other than C<resume>, and you B<must not> call C<resume> |
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without a previous call to C<suspend>. |
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Calling C<suspend>/C<resume> has the side effect of updating the event |
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loop time (see C<now_update>). |
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1.73 |
=item $backend = EV::backend |
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=item $backend = $loop->backend |
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Returns an integer describing the backend used by libev (EV::BACKEND_SELECT |
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or EV::BACKEND_EPOLL). |
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|
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1.138 |
=item $active = EV::run [$flags] |
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=item $active = $loop->run ([$flags]) |
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|
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1.20 |
Begin checking for events and calling callbacks. It returns when a |
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callback calls EV::break or the flags are nonzero (in which case the |
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1.138 |
return value is true) or when there are no active watchers which reference |
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the loop (keepalive is true), in which case the return value will be |
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1.149 |
false. The return value can generally be interpreted as "if true, there is |
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1.138 |
more work left to do". |
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1.2 |
|
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1.20 |
The $flags argument can be one of the following: |
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1.2 |
|
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1.135 |
0 as above |
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EV::RUN_ONCE block at most once (wait, but do not loop) |
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EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait) |
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1.2 |
|
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1.133 |
=item EV::break [$how] |
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1.2 |
|
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=item $loop->break ([$how]) |
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1.73 |
|
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1.133 |
When called with no arguments or an argument of EV::BREAK_ONE, makes the |
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1.155 |
innermost call to EV::run return. |
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1.2 |
|
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1.155 |
When called with an argument of EV::BREAK_ALL, all calls to EV::run will |
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1.133 |
return as fast as possible. |
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When called with an argument of EV::BREAK_CANCEL, any pending break will |
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be cancelled. |
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1.2 |
|
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1.135 |
=item $count = EV::iteration |
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1.60 |
|
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1.135 |
=item $count = $loop->iteration |
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1.73 |
|
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1.60 |
Return the number of times the event loop has polled for new |
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1.108 |
events. Sometimes useful as a generation counter. |
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1.60 |
|
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1.48 |
=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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1.47 |
|
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1.73 |
=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
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1.47 |
This function rolls together an I/O and a timer watcher for a single |
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one-shot event without the need for managing a watcher object. |
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If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
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must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
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| EV::WRITE>, indicating the type of I/O event you want to wait for. If |
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you do not want to wait for some I/O event, specify C<undef> for |
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C<$fh_or_undef> and C<0> for C<$events>). |
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If timeout is C<undef> or negative, then there will be no |
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1.153 |
timeout. Otherwise an C<EV::timer> with this value will be started. |
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1.47 |
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When an error occurs or either the timeout or I/O watcher triggers, then |
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the callback will be called with the received event set (in general |
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1.77 |
you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, |
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1.126 |
C<EV::WRITE> and C<EV::TIMER>). |
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1.47 |
|
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EV::once doesn't return anything: the watchers stay active till either |
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of them triggers, then they will be stopped and freed, and the callback |
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invoked. |
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1.133 |
=item EV::feed_fd_event $fd, $revents |
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1.65 |
|
360 |
root |
1.73 |
=item $loop->feed_fd_event ($fd, $revents) |
361 |
|
|
|
362 |
root |
1.65 |
Feed an event on a file descriptor into EV. EV will react to this call as |
363 |
|
|
if the readyness notifications specified by C<$revents> (a combination of |
364 |
|
|
C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
365 |
|
|
|
366 |
root |
1.133 |
=item EV::feed_signal_event $signal |
367 |
|
|
|
368 |
|
|
Feed a signal event into the default loop. EV will react to this call as |
369 |
|
|
if the signal specified by C<$signal> had occured. |
370 |
|
|
|
371 |
|
|
=item EV::feed_signal $signal |
372 |
root |
1.65 |
|
373 |
root |
1.133 |
Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works |
374 |
|
|
regardless of which loop has registered the signal, and is mainly useful |
375 |
root |
1.158 |
for custom signal implementations. |
376 |
root |
1.65 |
|
377 |
root |
1.79 |
=item EV::set_io_collect_interval $time |
378 |
|
|
|
379 |
|
|
=item $loop->set_io_collect_interval ($time) |
380 |
|
|
|
381 |
|
|
=item EV::set_timeout_collect_interval $time |
382 |
|
|
|
383 |
|
|
=item $loop->set_timeout_collect_interval ($time) |
384 |
|
|
|
385 |
|
|
These advanced functions set the minimum block interval when polling for I/O events and the minimum |
386 |
|
|
wait interval for timer events. See the libev documentation at |
387 |
root |
1.104 |
L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> |
388 |
root |
1.105 |
(locally installed as F<EV::libev>) for a more detailed discussion. |
389 |
root |
1.79 |
|
390 |
root |
1.119 |
=item $count = EV::pending_count |
391 |
|
|
|
392 |
|
|
=item $count = $loop->pending_count |
393 |
|
|
|
394 |
|
|
Returns the number of currently pending watchers. |
395 |
|
|
|
396 |
|
|
=item EV::invoke_pending |
397 |
|
|
|
398 |
|
|
=item $loop->invoke_pending |
399 |
|
|
|
400 |
|
|
Invoke all currently pending watchers. |
401 |
|
|
|
402 |
root |
1.20 |
=back |
403 |
|
|
|
404 |
root |
1.65 |
|
405 |
root |
1.73 |
=head1 WATCHER OBJECTS |
406 |
root |
1.2 |
|
407 |
root |
1.20 |
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 |
root |
1.98 |
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 |
root |
1.2 |
|
416 |
root |
1.20 |
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 |
|
|
|
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 |
root |
1.108 |
type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
424 |
root |
1.62 |
EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
425 |
root |
1.126 |
(which can set both EV::READ and EV::WRITE bits). |
426 |
root |
1.20 |
|
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 |
root |
1.23 |
object is destroyed, so you I<need> to keep the watcher objects returned by |
433 |
root |
1.20 |
the constructors. |
434 |
|
|
|
435 |
root |
1.23 |
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 |
|
|
|
439 |
root |
1.54 |
=head2 COMMON WATCHER METHODS |
440 |
root |
1.20 |
|
441 |
root |
1.54 |
This section lists methods common to all watchers. |
442 |
root |
1.20 |
|
443 |
|
|
=over 4 |
444 |
root |
1.2 |
|
445 |
root |
1.20 |
=item $w->start |
446 |
|
|
|
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 |
root |
1.2 |
|
453 |
root |
1.20 |
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 |
root |
1.62 |
regardless of whether the watcher was active or not. |
456 |
root |
1.2 |
|
457 |
root |
1.20 |
=item $bool = $w->is_active |
458 |
root |
1.2 |
|
459 |
root |
1.20 |
Returns true if the watcher is active, false otherwise. |
460 |
|
|
|
461 |
root |
1.30 |
=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 |
|
|
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 |
|
|
}; |
471 |
|
|
$w->data ("print me!"); |
472 |
|
|
|
473 |
root |
1.20 |
=item $current_cb = $w->cb |
474 |
|
|
|
475 |
|
|
=item $old_cb = $w->cb ($new_cb) |
476 |
|
|
|
477 |
root |
1.23 |
Queries the callback on the watcher and optionally changes it. You can do |
478 |
|
|
this at any time without the watcher restarting. |
479 |
|
|
|
480 |
|
|
=item $current_priority = $w->priority |
481 |
|
|
|
482 |
|
|
=item $old_priority = $w->priority ($new_priority) |
483 |
|
|
|
484 |
|
|
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 |
root |
1.24 |
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 |
root |
1.23 |
normalised to the nearest valid priority. |
489 |
|
|
|
490 |
root |
1.50 |
The default priority of any newly-created watcher is 0. |
491 |
|
|
|
492 |
|
|
Note that the priority semantics have not yet been fleshed out and are |
493 |
|
|
subject to almost certain change. |
494 |
root |
1.20 |
|
495 |
root |
1.65 |
=item $w->invoke ($revents) |
496 |
root |
1.20 |
|
497 |
|
|
Call the callback *now* with the given event mask. |
498 |
|
|
|
499 |
root |
1.65 |
=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 = $w->clear_pending |
505 |
|
|
|
506 |
root |
1.78 |
If the watcher is pending, this function clears its pending status and |
507 |
|
|
returns its C<$revents> bitset (as if its callback was invoked). If the |
508 |
root |
1.65 |
watcher isn't pending it does nothing and returns C<0>. |
509 |
|
|
|
510 |
root |
1.50 |
=item $previous_state = $w->keepalive ($bool) |
511 |
|
|
|
512 |
root |
1.155 |
Normally, C<EV::run> will return when there are no active watchers |
513 |
root |
1.50 |
(which is a "deadlock" because no progress can be made anymore). This is |
514 |
root |
1.124 |
convenient because it allows you to start your watchers (and your jobs), |
515 |
root |
1.155 |
call C<EV::run> once and when it returns you know that all your jobs are |
516 |
root |
1.50 |
finished (or they forgot to register some watchers for their task :). |
517 |
|
|
|
518 |
root |
1.77 |
Sometimes, however, this gets in your way, for example when the module |
519 |
root |
1.155 |
that calls C<EV::run> (usually the main program) is not the same module |
520 |
root |
1.50 |
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 |
root |
1.155 |
handled, but you would not want to keep C<EV::run> from returning just |
523 |
root |
1.50 |
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 |
root |
1.155 |
though your watcher is active, it won't keep C<EV::run> from returning. |
527 |
root |
1.50 |
|
528 |
root |
1.108 |
The initial value for keepalive is true (enabled), and you can change it |
529 |
root |
1.50 |
any time. |
530 |
|
|
|
531 |
root |
1.62 |
Example: Register an I/O watcher for some UDP socket but do not keep the |
532 |
root |
1.50 |
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 |
root |
1.98 |
$udp_watcher->keepalive (0); |
537 |
root |
1.74 |
|
538 |
|
|
=item $loop = $w->loop |
539 |
|
|
|
540 |
|
|
Return the loop that this watcher is attached to. |
541 |
root |
1.20 |
|
542 |
root |
1.54 |
=back |
543 |
|
|
|
544 |
|
|
|
545 |
root |
1.73 |
=head1 WATCHER TYPES |
546 |
root |
1.54 |
|
547 |
|
|
Each of the following subsections describes a single watcher type. |
548 |
|
|
|
549 |
root |
1.62 |
=head3 I/O WATCHERS - is this file descriptor readable or writable? |
550 |
root |
1.54 |
|
551 |
|
|
=over 4 |
552 |
|
|
|
553 |
root |
1.20 |
=item $w = EV::io $fileno_or_fh, $eventmask, $callback |
554 |
root |
1.2 |
|
555 |
root |
1.20 |
=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
556 |
root |
1.7 |
|
557 |
root |
1.76 |
=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
558 |
root |
1.73 |
|
559 |
|
|
=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
560 |
|
|
|
561 |
root |
1.20 |
As long as the returned watcher object is alive, call the C<$callback> |
562 |
root |
1.54 |
when at least one of events specified in C<$eventmask> occurs. |
563 |
root |
1.2 |
|
564 |
root |
1.20 |
The $eventmask can be one or more of these constants ORed together: |
565 |
root |
1.2 |
|
566 |
|
|
EV::READ wait until read() wouldn't block anymore |
567 |
|
|
EV::WRITE wait until write() wouldn't block anymore |
568 |
root |
1.7 |
|
569 |
root |
1.20 |
The C<io_ns> variant doesn't start (activate) the newly created watcher. |
570 |
root |
1.2 |
|
571 |
root |
1.20 |
=item $w->set ($fileno_or_fh, $eventmask) |
572 |
root |
1.10 |
|
573 |
root |
1.20 |
Reconfigures the watcher, see the constructor above for details. Can be |
574 |
|
|
called at any time. |
575 |
root |
1.10 |
|
576 |
root |
1.20 |
=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 |
root |
1.10 |
|
582 |
root |
1.20 |
=item $current_eventmask = $w->events |
583 |
|
|
|
584 |
|
|
=item $old_eventmask = $w->events ($new_eventmask) |
585 |
root |
1.10 |
|
586 |
root |
1.20 |
Returns the previously set event mask and optionally set a new one. |
587 |
root |
1.10 |
|
588 |
root |
1.54 |
=back |
589 |
|
|
|
590 |
|
|
|
591 |
|
|
=head3 TIMER WATCHERS - relative and optionally repeating timeouts |
592 |
|
|
|
593 |
|
|
=over 4 |
594 |
root |
1.10 |
|
595 |
root |
1.20 |
=item $w = EV::timer $after, $repeat, $callback |
596 |
root |
1.2 |
|
597 |
root |
1.20 |
=item $w = EV::timer_ns $after, $repeat, $callback |
598 |
root |
1.2 |
|
599 |
root |
1.73 |
=item $w = $loop->timer ($after, $repeat, $callback) |
600 |
|
|
|
601 |
|
|
=item $w = $loop->timer_ns ($after, $repeat, $callback) |
602 |
|
|
|
603 |
root |
1.150 |
Calls the callback after C<$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 $after) after the callback returns. |
606 |
root |
1.2 |
|
607 |
root |
1.20 |
This means that the callback would be called roughly after C<$after> |
608 |
root |
1.39 |
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 |
root |
1.2 |
|
613 |
root |
1.39 |
The timer is based on a monotonic clock, that is, if somebody is sitting |
614 |
root |
1.20 |
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 |
root |
1.2 |
|
617 |
root |
1.20 |
The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
618 |
|
|
|
619 |
root |
1.147 |
=item $w->set ($after, $repeat = 0) |
620 |
root |
1.20 |
|
621 |
root |
1.54 |
Reconfigures the watcher, see the constructor above for details. Can be called at |
622 |
root |
1.20 |
any time. |
623 |
|
|
|
624 |
|
|
=item $w->again |
625 |
|
|
|
626 |
root |
1.147 |
=item $w->again ($repeat) |
627 |
|
|
|
628 |
root |
1.20 |
Similar to the C<start> method, but has special semantics for repeating timers: |
629 |
|
|
|
630 |
root |
1.39 |
If the timer is active and non-repeating, it will be stopped. |
631 |
|
|
|
632 |
root |
1.20 |
If the timer is active and repeating, reset the timeout to occur |
633 |
|
|
C<$repeat> seconds after now. |
634 |
|
|
|
635 |
root |
1.39 |
If the timer is inactive and repeating, start it using the repeat value. |
636 |
root |
1.20 |
|
637 |
|
|
Otherwise do nothing. |
638 |
|
|
|
639 |
|
|
This behaviour is useful when you have a timeout for some IO |
640 |
|
|
operation. You create a timer object with the same value for C<$after> and |
641 |
|
|
C<$repeat>, and then, in the read/write watcher, run the C<again> method |
642 |
|
|
on the timeout. |
643 |
|
|
|
644 |
root |
1.147 |
If called with a C<$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 |
root |
1.54 |
=back |
652 |
|
|
|
653 |
|
|
|
654 |
|
|
=head3 PERIODIC WATCHERS - to cron or not to cron? |
655 |
|
|
|
656 |
|
|
=over 4 |
657 |
root |
1.20 |
|
658 |
root |
1.30 |
=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
659 |
root |
1.20 |
|
660 |
root |
1.30 |
=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
661 |
|
|
|
662 |
root |
1.73 |
=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
663 |
|
|
|
664 |
|
|
=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
665 |
|
|
|
666 |
root |
1.30 |
Similar to EV::timer, but is not based on relative timeouts but on |
667 |
|
|
absolute times. Apart from creating "simple" timers that trigger "at" the |
668 |
|
|
specified time, it can also be used for non-drifting absolute timers and |
669 |
|
|
more complex, cron-like, setups that are not adversely affected by time |
670 |
|
|
jumps (i.e. when the system clock is changed by explicit date -s or other |
671 |
|
|
means such as ntpd). It is also the most complex watcher type in EV. |
672 |
|
|
|
673 |
|
|
It has three distinct "modes": |
674 |
|
|
|
675 |
|
|
=over 4 |
676 |
root |
1.2 |
|
677 |
root |
1.30 |
=item * absolute timer ($interval = $reschedule_cb = 0) |
678 |
root |
1.2 |
|
679 |
root |
1.30 |
This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
680 |
|
|
will not adjust when a time jump occurs, that is, if it is to be run |
681 |
|
|
at January 1st 2011 then it will run when the system time reaches or |
682 |
|
|
surpasses this time. |
683 |
root |
1.2 |
|
684 |
root |
1.85 |
=item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
685 |
root |
1.2 |
|
686 |
root |
1.30 |
In this mode the watcher will always be scheduled to time out at the |
687 |
root |
1.151 |
next C<$at + N * $interval> time (for the lowest integer N) and then repeat, |
688 |
|
|
regardless of any time jumps. Note that, since C<N> can be negative, the |
689 |
|
|
first trigger can happen before C<$at>. |
690 |
root |
1.30 |
|
691 |
|
|
This can be used to create timers that do not drift with respect to system |
692 |
|
|
time: |
693 |
|
|
|
694 |
|
|
my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
695 |
|
|
|
696 |
|
|
That doesn't mean there will always be 3600 seconds in between triggers, |
697 |
root |
1.141 |
but only that the the callback will be called when the system time shows a |
698 |
root |
1.30 |
full hour (UTC). |
699 |
root |
1.2 |
|
700 |
root |
1.7 |
Another way to think about it (for the mathematically inclined) is that |
701 |
root |
1.30 |
EV::periodic will try to run the callback in this mode at the next |
702 |
|
|
possible time where C<$time = $at (mod $interval)>, regardless of any time |
703 |
|
|
jumps. |
704 |
|
|
|
705 |
|
|
=item * manual reschedule mode ($reschedule_cb = coderef) |
706 |
|
|
|
707 |
root |
1.37 |
In this mode $interval and $at are both being ignored. Instead, each |
708 |
|
|
time the periodic watcher gets scheduled, the reschedule callback |
709 |
|
|
($reschedule_cb) will be called with the watcher as first, and the current |
710 |
|
|
time as second argument. |
711 |
root |
1.30 |
|
712 |
root |
1.31 |
I<This callback MUST NOT stop or destroy this or any other periodic |
713 |
root |
1.94 |
watcher, ever, and MUST NOT call any event loop functions or methods>. If |
714 |
|
|
you need to stop it, return 1e30 and stop it afterwards. You may create |
715 |
root |
1.153 |
and start an C<EV::prepare> watcher for this task. |
716 |
root |
1.30 |
|
717 |
|
|
It must return the next time to trigger, based on the passed time value |
718 |
root |
1.94 |
(that is, the lowest time value larger than or equal to to the second |
719 |
|
|
argument). It will usually be called just before the callback will be |
720 |
|
|
triggered, but might be called at other times, too. |
721 |
root |
1.30 |
|
722 |
|
|
This can be used to create very complex timers, such as a timer that |
723 |
root |
1.152 |
triggers on each midnight, local time (actually one day after the last |
724 |
|
|
midnight, to keep the example simple): |
725 |
root |
1.30 |
|
726 |
|
|
my $daily = EV::periodic 0, 0, sub { |
727 |
|
|
my ($w, $now) = @_; |
728 |
|
|
|
729 |
|
|
use Time::Local (); |
730 |
|
|
my (undef, undef, undef, $d, $m, $y) = localtime $now; |
731 |
root |
1.152 |
Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y |
732 |
root |
1.30 |
}, sub { |
733 |
|
|
print "it's midnight or likely shortly after, now\n"; |
734 |
|
|
}; |
735 |
root |
1.7 |
|
736 |
root |
1.30 |
=back |
737 |
root |
1.20 |
|
738 |
|
|
The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
739 |
root |
1.2 |
|
740 |
root |
1.30 |
=item $w->set ($at, $interval, $reschedule_cb) |
741 |
root |
1.11 |
|
742 |
root |
1.54 |
Reconfigures the watcher, see the constructor above for details. Can be called at |
743 |
root |
1.20 |
any time. |
744 |
|
|
|
745 |
root |
1.30 |
=item $w->again |
746 |
|
|
|
747 |
|
|
Simply stops and starts the watcher again. |
748 |
|
|
|
749 |
root |
1.71 |
=item $time = $w->at |
750 |
|
|
|
751 |
|
|
Return the time that the watcher is expected to trigger next. |
752 |
|
|
|
753 |
root |
1.54 |
=back |
754 |
|
|
|
755 |
|
|
|
756 |
|
|
=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
757 |
|
|
|
758 |
|
|
=over 4 |
759 |
root |
1.20 |
|
760 |
|
|
=item $w = EV::signal $signal, $callback |
761 |
|
|
|
762 |
|
|
=item $w = EV::signal_ns $signal, $callback |
763 |
root |
1.11 |
|
764 |
root |
1.122 |
=item $w = $loop->signal ($signal, $callback) |
765 |
|
|
|
766 |
|
|
=item $w = $loop->signal_ns ($signal, $callback) |
767 |
|
|
|
768 |
root |
1.54 |
Call the callback when $signal is received (the signal can be specified by |
769 |
|
|
number or by name, just as with C<kill> or C<%SIG>). |
770 |
root |
1.2 |
|
771 |
root |
1.122 |
Only one event loop can grab a given signal - attempting to grab the same |
772 |
|
|
signal from two EV loops will crash the program immediately or cause data |
773 |
|
|
corruption. |
774 |
|
|
|
775 |
root |
1.11 |
EV will grab the signal for the process (the kernel only allows one |
776 |
root |
1.20 |
component to receive a signal at a time) when you start a signal watcher, |
777 |
|
|
and removes it again when you stop it. Perl does the same when you |
778 |
root |
1.54 |
add/remove callbacks to C<%SIG>, so watch out. |
779 |
root |
1.20 |
|
780 |
|
|
You can have as many signal watchers per signal as you want. |
781 |
root |
1.2 |
|
782 |
root |
1.20 |
The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
783 |
root |
1.2 |
|
784 |
root |
1.20 |
=item $w->set ($signal) |
785 |
root |
1.2 |
|
786 |
root |
1.54 |
Reconfigures the watcher, see the constructor above for details. Can be |
787 |
|
|
called at any time. |
788 |
root |
1.20 |
|
789 |
root |
1.22 |
=item $current_signum = $w->signal |
790 |
|
|
|
791 |
|
|
=item $old_signum = $w->signal ($new_signal) |
792 |
|
|
|
793 |
|
|
Returns the previously set signal (always as a number not name) and |
794 |
|
|
optionally set a new one. |
795 |
|
|
|
796 |
root |
1.54 |
=back |
797 |
|
|
|
798 |
|
|
|
799 |
|
|
=head3 CHILD WATCHERS - watch out for process status changes |
800 |
|
|
|
801 |
|
|
=over 4 |
802 |
root |
1.20 |
|
803 |
root |
1.82 |
=item $w = EV::child $pid, $trace, $callback |
804 |
root |
1.20 |
|
805 |
root |
1.82 |
=item $w = EV::child_ns $pid, $trace, $callback |
806 |
root |
1.20 |
|
807 |
root |
1.82 |
=item $w = $loop->child ($pid, $trace, $callback) |
808 |
root |
1.73 |
|
809 |
root |
1.82 |
=item $w = $loop->child_ns ($pid, $trace, $callback) |
810 |
root |
1.73 |
|
811 |
root |
1.82 |
Call the callback when a status change for pid C<$pid> (or any pid |
812 |
|
|
if C<$pid> is 0) has been received (a status change happens when the |
813 |
|
|
process terminates or is killed, or, when trace is true, additionally when |
814 |
|
|
it is stopped or continued). More precisely: when the process receives |
815 |
root |
1.54 |
a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
816 |
root |
1.20 |
changed/zombie children and call the callback. |
817 |
|
|
|
818 |
root |
1.54 |
It is valid (and fully supported) to install a child watcher after a child |
819 |
|
|
has exited but before the event loop has started its next iteration (for |
820 |
|
|
example, first you C<fork>, then the new child process might exit, and |
821 |
|
|
only then do you install a child watcher in the parent for the new pid). |
822 |
|
|
|
823 |
|
|
You can access both exit (or tracing) status and pid by using the |
824 |
|
|
C<rstatus> and C<rpid> methods on the watcher object. |
825 |
root |
1.20 |
|
826 |
root |
1.54 |
You can have as many pid watchers per pid as you want, they will all be |
827 |
|
|
called. |
828 |
root |
1.20 |
|
829 |
|
|
The C<child_ns> variant doesn't start (activate) the newly created watcher. |
830 |
|
|
|
831 |
root |
1.82 |
=item $w->set ($pid, $trace) |
832 |
root |
1.1 |
|
833 |
root |
1.54 |
Reconfigures the watcher, see the constructor above for details. Can be called at |
834 |
root |
1.20 |
any time. |
835 |
root |
1.2 |
|
836 |
root |
1.22 |
=item $current_pid = $w->pid |
837 |
|
|
|
838 |
|
|
Returns the previously set process id and optionally set a new one. |
839 |
|
|
|
840 |
root |
1.27 |
=item $exit_status = $w->rstatus |
841 |
|
|
|
842 |
|
|
Return the exit/wait status (as returned by waitpid, see the waitpid entry |
843 |
|
|
in perlfunc). |
844 |
|
|
|
845 |
|
|
=item $pid = $w->rpid |
846 |
|
|
|
847 |
|
|
Return the pid of the awaited child (useful when you have installed a |
848 |
|
|
watcher for all pids). |
849 |
|
|
|
850 |
root |
1.54 |
=back |
851 |
|
|
|
852 |
|
|
|
853 |
root |
1.56 |
=head3 STAT WATCHERS - did the file attributes just change? |
854 |
|
|
|
855 |
|
|
=over 4 |
856 |
|
|
|
857 |
|
|
=item $w = EV::stat $path, $interval, $callback |
858 |
|
|
|
859 |
|
|
=item $w = EV::stat_ns $path, $interval, $callback |
860 |
|
|
|
861 |
root |
1.73 |
=item $w = $loop->stat ($path, $interval, $callback) |
862 |
|
|
|
863 |
|
|
=item $w = $loop->stat_ns ($path, $interval, $callback) |
864 |
|
|
|
865 |
root |
1.56 |
Call the callback when a file status change has been detected on |
866 |
|
|
C<$path>. The C<$path> does not need to exist, changing from "path exists" |
867 |
|
|
to "path does not exist" is a status change like any other. |
868 |
|
|
|
869 |
|
|
The C<$interval> is a recommended polling interval for systems where |
870 |
|
|
OS-supported change notifications don't exist or are not supported. If |
871 |
|
|
you use C<0> then an unspecified default is used (which is highly |
872 |
|
|
recommended!), which is to be expected to be around five seconds usually. |
873 |
|
|
|
874 |
|
|
This watcher type is not meant for massive numbers of stat watchers, |
875 |
|
|
as even with OS-supported change notifications, this can be |
876 |
|
|
resource-intensive. |
877 |
|
|
|
878 |
|
|
The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
879 |
|
|
|
880 |
root |
1.57 |
=item ... = $w->stat |
881 |
|
|
|
882 |
|
|
This call is very similar to the perl C<stat> built-in: It stats (using |
883 |
|
|
C<lstat>) the path specified in the watcher and sets perls stat cache (as |
884 |
|
|
well as EV's idea of the current stat values) to the values found. |
885 |
|
|
|
886 |
|
|
In scalar context, a boolean is return indicating success or failure of |
887 |
|
|
the stat. In list context, the same 13-value list as with stat is returned |
888 |
|
|
(except that the blksize and blocks fields are not reliable). |
889 |
|
|
|
890 |
|
|
In the case of an error, errno is set to C<ENOENT> (regardless of the |
891 |
|
|
actual error value) and the C<nlink> value is forced to zero (if the stat |
892 |
|
|
was successful then nlink is guaranteed to be non-zero). |
893 |
|
|
|
894 |
|
|
See also the next two entries for more info. |
895 |
|
|
|
896 |
|
|
=item ... = $w->attr |
897 |
|
|
|
898 |
|
|
Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
899 |
|
|
the values most recently detected by EV. See the next entry for more info. |
900 |
|
|
|
901 |
|
|
=item ... = $w->prev |
902 |
|
|
|
903 |
|
|
Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
904 |
|
|
the previous set of values, before the change. |
905 |
|
|
|
906 |
|
|
That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
907 |
|
|
to the values found I<before> a change was detected, while C<< $w->attr >> |
908 |
|
|
returns the values found leading to the change detection. The difference (if any) |
909 |
|
|
between C<prev> and C<attr> is what triggered the callback. |
910 |
|
|
|
911 |
|
|
If you did something to the filesystem object and do not want to trigger |
912 |
|
|
yet another change, you can call C<stat> to update EV's idea of what the |
913 |
|
|
current attributes are. |
914 |
|
|
|
915 |
root |
1.56 |
=item $w->set ($path, $interval) |
916 |
|
|
|
917 |
|
|
Reconfigures the watcher, see the constructor above for details. Can be |
918 |
|
|
called at any time. |
919 |
|
|
|
920 |
|
|
=item $current_path = $w->path |
921 |
|
|
|
922 |
|
|
=item $old_path = $w->path ($new_path) |
923 |
|
|
|
924 |
|
|
Returns the previously set path and optionally set a new one. |
925 |
|
|
|
926 |
|
|
=item $current_interval = $w->interval |
927 |
|
|
|
928 |
|
|
=item $old_interval = $w->interval ($new_interval) |
929 |
|
|
|
930 |
|
|
Returns the previously set interval and optionally set a new one. Can be |
931 |
|
|
used to query the actual interval used. |
932 |
|
|
|
933 |
|
|
=back |
934 |
|
|
|
935 |
|
|
|
936 |
root |
1.54 |
=head3 IDLE WATCHERS - when you've got nothing better to do... |
937 |
|
|
|
938 |
|
|
=over 4 |
939 |
root |
1.2 |
|
940 |
root |
1.20 |
=item $w = EV::idle $callback |
941 |
root |
1.2 |
|
942 |
root |
1.20 |
=item $w = EV::idle_ns $callback |
943 |
root |
1.2 |
|
944 |
root |
1.73 |
=item $w = $loop->idle ($callback) |
945 |
|
|
|
946 |
|
|
=item $w = $loop->idle_ns ($callback) |
947 |
|
|
|
948 |
root |
1.62 |
Call the callback when there are no other pending watchers of the same or |
949 |
|
|
higher priority (excluding check, prepare and other idle watchers of the |
950 |
|
|
same or lower priority, of course). They are called idle watchers because |
951 |
|
|
when the watcher is the highest priority pending event in the process, the |
952 |
|
|
process is considered to be idle at that priority. |
953 |
|
|
|
954 |
|
|
If you want a watcher that is only ever called when I<no> other events are |
955 |
|
|
outstanding you have to set the priority to C<EV::MINPRI>. |
956 |
root |
1.2 |
|
957 |
root |
1.20 |
The process will not block as long as any idle watchers are active, and |
958 |
|
|
they will be called repeatedly until stopped. |
959 |
root |
1.2 |
|
960 |
root |
1.62 |
For example, if you have idle watchers at priority C<0> and C<1>, and |
961 |
|
|
an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
962 |
|
|
and the I/O watcher will always run when ready. Only when the idle watcher |
963 |
|
|
at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
964 |
|
|
pending with the C<0>-priority idle watcher be invoked. |
965 |
|
|
|
966 |
root |
1.20 |
The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
967 |
root |
1.2 |
|
968 |
root |
1.54 |
=back |
969 |
|
|
|
970 |
|
|
|
971 |
|
|
=head3 PREPARE WATCHERS - customise your event loop! |
972 |
|
|
|
973 |
|
|
=over 4 |
974 |
root |
1.2 |
|
975 |
root |
1.20 |
=item $w = EV::prepare $callback |
976 |
root |
1.1 |
|
977 |
root |
1.20 |
=item $w = EV::prepare_ns $callback |
978 |
root |
1.1 |
|
979 |
root |
1.73 |
=item $w = $loop->prepare ($callback) |
980 |
|
|
|
981 |
root |
1.76 |
=item $w = $loop->prepare_ns ($callback) |
982 |
root |
1.73 |
|
983 |
root |
1.20 |
Call the callback just before the process would block. You can still |
984 |
|
|
create/modify any watchers at this point. |
985 |
root |
1.1 |
|
986 |
root |
1.20 |
See the EV::check watcher, below, for explanations and an example. |
987 |
root |
1.2 |
|
988 |
root |
1.20 |
The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
989 |
root |
1.2 |
|
990 |
root |
1.54 |
=back |
991 |
|
|
|
992 |
|
|
|
993 |
|
|
=head3 CHECK WATCHERS - customise your event loop even more! |
994 |
|
|
|
995 |
|
|
=over 4 |
996 |
root |
1.2 |
|
997 |
root |
1.20 |
=item $w = EV::check $callback |
998 |
root |
1.2 |
|
999 |
root |
1.20 |
=item $w = EV::check_ns $callback |
1000 |
root |
1.10 |
|
1001 |
root |
1.73 |
=item $w = $loop->check ($callback) |
1002 |
|
|
|
1003 |
|
|
=item $w = $loop->check_ns ($callback) |
1004 |
|
|
|
1005 |
root |
1.20 |
Call the callback just after the process wakes up again (after it has |
1006 |
|
|
gathered events), but before any other callbacks have been invoked. |
1007 |
root |
1.10 |
|
1008 |
root |
1.128 |
This can be used to integrate other event-based software into the EV |
1009 |
root |
1.20 |
mainloop: You register a prepare callback and in there, you create io and |
1010 |
|
|
timer watchers as required by the other software. Here is a real-world |
1011 |
|
|
example of integrating Net::SNMP (with some details left out): |
1012 |
root |
1.10 |
|
1013 |
root |
1.20 |
our @snmp_watcher; |
1014 |
root |
1.2 |
|
1015 |
root |
1.20 |
our $snmp_prepare = EV::prepare sub { |
1016 |
|
|
# do nothing unless active |
1017 |
|
|
$dispatcher->{_event_queue_h} |
1018 |
|
|
or return; |
1019 |
root |
1.2 |
|
1020 |
root |
1.20 |
# make the dispatcher handle any outstanding stuff |
1021 |
root |
1.45 |
... not shown |
1022 |
root |
1.2 |
|
1023 |
root |
1.62 |
# create an I/O watcher for each and every socket |
1024 |
root |
1.20 |
@snmp_watcher = ( |
1025 |
|
|
(map { EV::io $_, EV::READ, sub { } } |
1026 |
|
|
keys %{ $dispatcher->{_descriptors} }), |
1027 |
root |
1.45 |
|
1028 |
|
|
EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
1029 |
|
|
? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
1030 |
|
|
0, sub { }, |
1031 |
root |
1.20 |
); |
1032 |
|
|
}; |
1033 |
root |
1.2 |
|
1034 |
root |
1.45 |
The callbacks are irrelevant (and are not even being called), the |
1035 |
|
|
only purpose of those watchers is to wake up the process as soon as |
1036 |
|
|
one of those events occurs (socket readable, or timer timed out). The |
1037 |
|
|
corresponding EV::check watcher will then clean up: |
1038 |
root |
1.2 |
|
1039 |
root |
1.20 |
our $snmp_check = EV::check sub { |
1040 |
|
|
# destroy all watchers |
1041 |
|
|
@snmp_watcher = (); |
1042 |
root |
1.2 |
|
1043 |
root |
1.20 |
# make the dispatcher handle any new stuff |
1044 |
root |
1.45 |
... not shown |
1045 |
root |
1.20 |
}; |
1046 |
root |
1.2 |
|
1047 |
root |
1.20 |
The callbacks of the created watchers will not be called as the watchers |
1048 |
root |
1.108 |
are destroyed before this can happen (remember EV::check gets called |
1049 |
root |
1.20 |
first). |
1050 |
root |
1.2 |
|
1051 |
root |
1.20 |
The C<check_ns> variant doesn't start (activate) the newly created watcher. |
1052 |
root |
1.1 |
|
1053 |
root |
1.128 |
=item EV::CHECK constant issues |
1054 |
|
|
|
1055 |
|
|
Like all other watcher types, there is a bitmask constant for use in |
1056 |
|
|
C<$revents> and other places. The C<EV::CHECK> is special as it has |
1057 |
|
|
the same name as the C<CHECK> sub called by Perl. This doesn't cause |
1058 |
|
|
big issues on newer perls (beginning with 5.8.9), but it means thatthe |
1059 |
|
|
constant must be I<inlined>, i.e. runtime calls will not work. That means |
1060 |
|
|
that as long as you always C<use EV> and then C<EV::CHECK> you are on the |
1061 |
|
|
safe side. |
1062 |
|
|
|
1063 |
root |
1.1 |
=back |
1064 |
|
|
|
1065 |
root |
1.54 |
|
1066 |
root |
1.56 |
=head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
1067 |
root |
1.54 |
|
1068 |
root |
1.56 |
Fork watchers are called when a C<fork ()> was detected. The invocation |
1069 |
|
|
is done before the event loop blocks next and before C<check> watchers |
1070 |
|
|
are being called, and only in the child after the fork. |
1071 |
root |
1.54 |
|
1072 |
root |
1.56 |
=over 4 |
1073 |
root |
1.54 |
|
1074 |
root |
1.56 |
=item $w = EV::fork $callback |
1075 |
root |
1.54 |
|
1076 |
root |
1.56 |
=item $w = EV::fork_ns $callback |
1077 |
root |
1.54 |
|
1078 |
root |
1.73 |
=item $w = $loop->fork ($callback) |
1079 |
|
|
|
1080 |
|
|
=item $w = $loop->fork_ns ($callback) |
1081 |
|
|
|
1082 |
root |
1.56 |
Call the callback before the event loop is resumed in the child process |
1083 |
|
|
after a fork. |
1084 |
root |
1.54 |
|
1085 |
root |
1.56 |
The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
1086 |
root |
1.54 |
|
1087 |
|
|
=back |
1088 |
|
|
|
1089 |
|
|
|
1090 |
root |
1.79 |
=head3 EMBED WATCHERS - when one backend isn't enough... |
1091 |
|
|
|
1092 |
|
|
This is a rather advanced watcher type that lets you embed one event loop |
1093 |
|
|
into another (currently only IO events are supported in the embedded |
1094 |
|
|
loop, other types of watchers might be handled in a delayed or incorrect |
1095 |
|
|
fashion and must not be used). |
1096 |
|
|
|
1097 |
|
|
See the libev documentation at |
1098 |
|
|
L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> |
1099 |
root |
1.105 |
(locally installed as F<EV::libev>) for more details. |
1100 |
root |
1.79 |
|
1101 |
|
|
In short, this watcher is most useful on BSD systems without working |
1102 |
|
|
kqueue to still be able to handle a large number of sockets: |
1103 |
|
|
|
1104 |
root |
1.98 |
my $socket_loop; |
1105 |
|
|
|
1106 |
|
|
# check wether we use SELECT or POLL _and_ KQUEUE is supported |
1107 |
|
|
if ( |
1108 |
|
|
(EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
1109 |
|
|
&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
1110 |
|
|
) { |
1111 |
|
|
# use kqueue for sockets |
1112 |
|
|
$socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
1113 |
|
|
} |
1114 |
|
|
|
1115 |
|
|
# use the default loop otherwise |
1116 |
|
|
$socket_loop ||= EV::default_loop; |
1117 |
root |
1.79 |
|
1118 |
|
|
=over 4 |
1119 |
|
|
|
1120 |
root |
1.101 |
=item $w = EV::embed $otherloop[, $callback] |
1121 |
root |
1.79 |
|
1122 |
root |
1.101 |
=item $w = EV::embed_ns $otherloop[, $callback] |
1123 |
root |
1.79 |
|
1124 |
root |
1.101 |
=item $w = $loop->embed ($otherloop[, $callback]) |
1125 |
root |
1.79 |
|
1126 |
root |
1.101 |
=item $w = $loop->embed_ns ($otherloop[, $callback]) |
1127 |
root |
1.79 |
|
1128 |
|
|
Call the callback when the embedded event loop (C<$otherloop>) has any |
1129 |
root |
1.101 |
I/O activity. The C<$callback> is optional: if it is missing, then the |
1130 |
|
|
embedded event loop will be managed automatically (which is recommended), |
1131 |
|
|
otherwise you have to invoke C<sweep> yourself. |
1132 |
root |
1.79 |
|
1133 |
|
|
The C<embed_ns> variant doesn't start (activate) the newly created watcher. |
1134 |
|
|
|
1135 |
|
|
=back |
1136 |
|
|
|
1137 |
root |
1.84 |
=head3 ASYNC WATCHERS - how to wake up another event loop |
1138 |
|
|
|
1139 |
root |
1.116 |
Async watchers are provided by EV, but have little use in perl directly, |
1140 |
|
|
as perl neither supports threads running in parallel nor direct access to |
1141 |
|
|
signal handlers or other contexts where they could be of value. |
1142 |
root |
1.84 |
|
1143 |
|
|
It is, however, possible to use them from the XS level. |
1144 |
|
|
|
1145 |
|
|
Please see the libev documentation for further details. |
1146 |
|
|
|
1147 |
root |
1.87 |
=over 4 |
1148 |
|
|
|
1149 |
|
|
=item $w = EV::async $callback |
1150 |
|
|
|
1151 |
|
|
=item $w = EV::async_ns $callback |
1152 |
|
|
|
1153 |
root |
1.138 |
=item $w = $loop->async ($callback) |
1154 |
|
|
|
1155 |
|
|
=item $w = $loop->async_ns ($callback) |
1156 |
|
|
|
1157 |
root |
1.87 |
=item $w->send |
1158 |
|
|
|
1159 |
|
|
=item $bool = $w->async_pending |
1160 |
|
|
|
1161 |
|
|
=back |
1162 |
|
|
|
1163 |
root |
1.138 |
=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away |
1164 |
|
|
|
1165 |
|
|
Cleanup watchers are not supported on the Perl level, they can only be |
1166 |
|
|
used via XS currently. |
1167 |
|
|
|
1168 |
root |
1.79 |
|
1169 |
root |
1.61 |
=head1 PERL SIGNALS |
1170 |
|
|
|
1171 |
|
|
While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
1172 |
|
|
with EV is as the same as any other C library: Perl-signals will only be |
1173 |
|
|
handled when Perl runs, which means your signal handler might be invoked |
1174 |
|
|
only the next time an event callback is invoked. |
1175 |
|
|
|
1176 |
|
|
The solution is to use EV signal watchers (see C<EV::signal>), which will |
1177 |
|
|
ensure proper operations with regards to other event watchers. |
1178 |
|
|
|
1179 |
|
|
If you cannot do this for whatever reason, you can also force a watcher |
1180 |
|
|
to be called on every event loop iteration by installing a C<EV::check> |
1181 |
|
|
watcher: |
1182 |
|
|
|
1183 |
|
|
my $async_check = EV::check sub { }; |
1184 |
|
|
|
1185 |
root |
1.75 |
This ensures that perl gets into control for a short time to handle any |
1186 |
|
|
pending signals, and also ensures (slightly) slower overall operation. |
1187 |
root |
1.61 |
|
1188 |
root |
1.116 |
=head1 ITHREADS |
1189 |
root |
1.13 |
|
1190 |
root |
1.116 |
Ithreads are not supported by this module in any way. Perl pseudo-threads |
1191 |
|
|
is evil stuff and must die. Real threads as provided by Coro are fully |
1192 |
|
|
supported (and enhanced support is available via L<Coro::EV>). |
1193 |
root |
1.46 |
|
1194 |
|
|
=head1 FORK |
1195 |
|
|
|
1196 |
|
|
Most of the "improved" event delivering mechanisms of modern operating |
1197 |
|
|
systems have quite a few problems with fork(2) (to put it bluntly: it is |
1198 |
|
|
not supported and usually destructive). Libev makes it possible to work |
1199 |
|
|
around this by having a function that recreates the kernel state after |
1200 |
|
|
fork in the child. |
1201 |
|
|
|
1202 |
|
|
On non-win32 platforms, this module requires the pthread_atfork |
1203 |
|
|
functionality to do this automatically for you. This function is quite |
1204 |
|
|
buggy on most BSDs, though, so YMMV. The overhead for this is quite |
1205 |
|
|
negligible, because everything the function currently does is set a flag |
1206 |
|
|
that is checked only when the event loop gets used the next time, so when |
1207 |
|
|
you do fork but not use EV, the overhead is minimal. |
1208 |
|
|
|
1209 |
|
|
On win32, there is no notion of fork so all this doesn't apply, of course. |
1210 |
root |
1.13 |
|
1211 |
root |
1.1 |
=cut |
1212 |
|
|
|
1213 |
root |
1.8 |
our $DIED = sub { |
1214 |
|
|
warn "EV: error in callback (ignoring): $@"; |
1215 |
|
|
}; |
1216 |
|
|
|
1217 |
root |
1.28 |
default_loop |
1218 |
root |
1.68 |
or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
1219 |
root |
1.1 |
|
1220 |
|
|
1; |
1221 |
|
|
|
1222 |
root |
1.3 |
=head1 SEE ALSO |
1223 |
|
|
|
1224 |
root |
1.130 |
L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS> |
1225 |
|
|
(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event |
1226 |
|
|
loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread |
1227 |
|
|
integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for |
1228 |
root |
1.90 |
event-loop agnostic and portable event driven programming. |
1229 |
root |
1.3 |
|
1230 |
root |
1.1 |
=head1 AUTHOR |
1231 |
|
|
|
1232 |
root |
1.98 |
Marc Lehmann <schmorp@schmorp.de> |
1233 |
|
|
http://home.schmorp.de/ |
1234 |
root |
1.1 |
|
1235 |
|
|
=cut |
1236 |
|
|
|