[ViewVC] Diff of: cvs/EV/EV.pm

Comparing EV/EV.pm (file contents):
Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC vs.
Revision 1.162 by root, Wed Jan 22 23:17:31 2020 UTC

 EV - perl interface to libev, a high performance full-featured event loop
 =head1 SYNOPSIS
-  use EV;
+   use EV;
+   # TIMERS
+   my $w = EV::timer 2, 0, sub {
+      warn "is called after 2s";
+   };
+   my $w = EV::timer 2, 2, sub {
+      warn "is called roughly every 2s (repeat = 2)";
+   };
+   undef $w; # destroy event watcher again
+   my $w = EV::periodic 0, 60, 0, sub {
+      warn "is called every minute, on the minute, exactly";
+   };
+   # IO
+   my $w = EV::io *STDIN, EV::READ, sub {
+      my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
+      warn "stdin is readable, you entered: ", <STDIN>;
+   };
+   # SIGNALS
+   my $w = EV::signal 'QUIT', sub {
+      warn "sigquit received\n";
+   };
+   # CHILD/PID STATUS CHANGES
-  # TIMERS
+   my $w = EV::child 666, 0, sub {
+      my ($w, $revents) = @_;
+      my $status = $w->rstatus;
+   };
-  my $w = EV::timer 2, 0, sub {
-     warn "is called after 2s";
-  };
-  my $w = EV::timer 2, 2, sub {
-     warn "is called roughly every 2s (repeat = 2)";
-  };
-  undef $w; # destroy event watcher again
-  my $w = EV::periodic 0, 60, 0, sub {
-     warn "is called every minute, on the minute, exactly";
-  };
-  # IO
-  my $w = EV::io *STDIN, EV::READ, sub {
-     my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
-     warn "stdin is readable, you entered: ", <STDIN>;
-  };
-  # SIGNALS
-  my $w = EV::signal 'QUIT', sub {
-     warn "sigquit received\n";
-  };
-  # CHILD/PID STATUS CHANGES
-  my $w = EV::child 666, sub {
-     my ($w, $revents) = @_;
-     my $status = $w->rstatus;
-  };
-  # STAT CHANGES
+   # STAT CHANGES
-  my $w = EV::stat "/etc/passwd", 10, sub {
+   my $w = EV::stat "/etc/passwd", 10, sub {
-     my ($w, $revents) = @_;
+      my ($w, $revents) = @_;
-     warn $w->path, " has changed somehow.\n";
+      warn $w->path, " has changed somehow.\n";
-  };
+   };
-  # MAINLOOP
+   # MAINLOOP
-  EV::loop;           # loop until EV::unloop is called or all watchers stop
+   EV::run;                # loop until EV::break is called or all watchers stop
-  EV::loop EV::LOOP_ONESHOT;  # block until at least one event could be handled
+   EV::run EV::RUN_ONCE;   # block until at least one event could be handled
-  EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
+   EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
+=head1 BEFORE YOU START USING THIS MODULE
+If you only need timer, I/O, signal, child and idle watchers and not the
+advanced functionality of this module, consider using L<AnyEvent> instead,
+specifically the simplified API described in L<AE>.
+When used with EV as backend, the L<AE> API is as fast as the native L<EV>
+API, but your programs/modules will still run with many other event loops.
 =head1 DESCRIPTION
 This module provides an interface to libev
 (L<http://software.schmorp.de/pkg/libev.html>). While the documentation
-below is comprehensive, one might also consult the documentation of libev
+below is comprehensive, one might also consult the documentation of
-itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on
+libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
-watcher semantics or some discussion on the available backends, or how to
+F<perldoc EV::libev>) for more subtle details on watcher semantics or some
-force a specific backend with C<LIBEV_FLAGS>, or just about in any case
+discussion on the available backends, or how to force a specific backend
-because it has much more detailed information.
+with C<LIBEV_FLAGS>, or just about in any case because it has much more
+detailed information.
+This module is very fast and scalable. It is actually so fast that you
+can use it through the L<AnyEvent> module, stay portable to other event
+loops (if you don't rely on any watcher types not available through it)
+and still be faster than with any other event loop currently supported in
+Perl.
+=head2 PORTING FROM EV 3.X to 4.X
+EV version 4 introduces a number of incompatible changes summarised
+here. According to the depreciation strategy used by libev, there is a
+compatibility layer in place so programs should continue to run unchanged
+(the XS interface lacks this layer, so programs using that one need to be
+updated).
+This compatibility layer will be switched off in some future release.
+All changes relevant to Perl are renames of symbols, functions and
+methods:
+  EV::loop          => EV::run
+  EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
+  EV::LOOP_ONESHOT  => EV::RUN_ONCE
+  EV::unloop        => EV::break
+  EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
+  EV::UNLOOP_ONE    => EV::BREAK_ONE
+  EV::UNLOOP_ALL    => EV::BREAK_ALL
+  EV::TIMEOUT       => EV::TIMER
+  EV::loop_count    => EV::iteration
+  EV::loop_depth    => EV::depth
+  EV::loop_verify   => EV::verify
+The loop object methods corresponding to the functions above have been
+similarly renamed.
+=head2 MODULE EXPORTS
+This module does not export any symbols.
 =cut
 package EV;
-use strict;
+use common::sense;
 BEGIN {
-   our $VERSION = '2.0';
+   our $VERSION = '4.31';
    use XSLoader;
+   local $^W = 0; # avoid spurious warning
    XSLoader::load "EV", $VERSION;
 }
 @EV::IO::ISA       =
 @EV::Timer::ISA    =
 @EV::Idle::ISA     =
 @EV::Prepare::ISA  =
 @EV::Check::ISA    =
 @EV::Embed::ISA    =
 @EV::Fork::ISA     =
+@EV::Async::ISA    =
    "EV::Watcher";
 @EV::Loop::Default::ISA = "EV::Loop";
+=head1 EVENT LOOPS
+EV supports multiple event loops: There is a single "default event loop"
+that can handle everything including signals and child watchers, and any
+number of "dynamic event loops" that can use different backends (with
+various limitations), but no child and signal watchers.
+You do not have to do anything to create the default event loop: When
+the module is loaded a suitable backend is selected on the premise of
+selecting a working backend (which for example rules out kqueue on most
+BSDs). Modules should, unless they have "special needs" always use the
+default loop as this is fastest (perl-wise), best supported by other
+modules (e.g. AnyEvent or Coro) and most portable event loop.
+For specific programs you can create additional event loops dynamically.
+If you want to take advantage of kqueue (which often works properly for
+sockets only) even though the default loop doesn't enable it, you can
+I<embed> a kqueue loop into the default loop: running the default loop
+will then also service the kqueue loop to some extent. See the example in
+the section about embed watchers for an example on how to achieve that.
+=over 4
+=item $loop = new EV::Loop [$flags]
+Create a new event loop as per the specified flags. Please refer to
+the C<ev_loop_new ()> function description in the libev documentation
+(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
+or locally-installed as F<EV::libev> manpage) for more info.
+The loop will automatically be destroyed when it is no longer referenced
+by any watcher and the loop object goes out of scope.
+If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
+is recommended, as only the default event loop is protected by this
+module. If you I<are> embedding this loop in the default loop, this is not
+necessary, as C<EV::embed> automatically does the right thing on fork.
+=item $loop->loop_fork
+Must be called after a fork in the child, before entering or continuing
+the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
+this function automatically, at some performance loss (refer to the libev
+documentation).
+=item $loop->verify
+Calls C<ev_verify> to make internal consistency checks (for debugging
+libev) and abort the program if any data structures were found to be
+corrupted.
+=item $loop = EV::default_loop [$flags]
+Return the default loop (which is a singleton object). Since this module
+already creates the default loop with default flags, specifying flags here
+will not have any effect unless you destroy the default loop first, which
+isn't supported. So in short: don't do it, and if you break it, you get to
+keep the pieces.
+=back
 =head1 BASIC INTERFACE
 =over 4
 throws an exception (with $@ containing the error). The default prints an
 informative message and continues.
 If this callback throws an exception it will be silently ignored.
+=item $flags = EV::supported_backends
+=item $flags = EV::recommended_backends
+=item $flags = EV::embeddable_backends
+Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
+instance of EV, the set of recommended backends (supposed to be good) for
+this platform and the set of embeddable backends (see EMBED WATCHERS).
+=item EV::sleep $seconds
+Block the process for the given number of (fractional) seconds.
 =item $time = EV::time
 Returns the current time in (fractional) seconds since the epoch.
 =item $time = EV::now
+=item $time = $loop->now
 Returns the time the last event loop iteration has been started. This
-is the time that (relative) timers are based on, and refering to it is
+is the time that (relative) timers are based on, and referring to it is
 usually faster then calling EV::time.
-=item $method = EV::method
+=item EV::now_update
+=item $loop->now_update
+Establishes the current time by querying the kernel, updating the time
+returned by C<EV::now> in the progress. This is a costly operation and
+is usually done automatically within C<EV::run>.
+This function is rarely useful, but when some event callback runs for a
+very long time without entering the event loop, updating libev's idea of
+the current time is a good idea.
+=item EV::suspend
+=item $loop->suspend
+=item EV::resume
+=item $loop->resume
+These two functions suspend and resume a loop, for use when the loop is
+not used for a while and timeouts should not be processed.
+A typical use case would be an interactive program such as a game:  When
+the user presses C<^Z> to suspend the game and resumes it an hour later it
+would be best to handle timeouts as if no time had actually passed while
+the program was suspended. This can be achieved by calling C<suspend>
+in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
+C<resume> directly afterwards to resume timer processing.
+Effectively, all C<timer> watchers will be delayed by the time spend
+between C<suspend> and C<resume>, and all C<periodic> watchers
+will be rescheduled (that is, they will lose any events that would have
+occured while suspended).
+After calling C<suspend> you B<must not> call I<any> function on the given
+loop other than C<resume>, and you B<must not> call C<resume>
+without a previous call to C<suspend>.
+Calling C<suspend>/C<resume> has the side effect of updating the event
+loop time (see C<now_update>).
+=item $backend = EV::backend
+=item $backend = $loop->backend
-Returns an integer describing the backend used by libev (EV::METHOD_SELECT
+Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
-or EV::METHOD_EPOLL).
+or EV::BACKEND_EPOLL).
-=item EV::loop [$flags]
+=item $active = EV::run [$flags]
+=item $active = $loop->run ([$flags])
 Begin checking for events and calling callbacks. It returns when a
-callback calls EV::unloop.
+callback calls EV::break or the flags are nonzero (in which case the
+return value is true) or when there are no active watchers which reference
+the loop (keepalive is true), in which case the return value will be
+false. The return value can generally be interpreted as "if true, there is
+more work left to do".
 The $flags argument can be one of the following:
-   0                  as above
+   0               as above
-   EV::LOOP_ONESHOT   block at most once (wait, but do not loop)
+   EV::RUN_ONCE    block at most once (wait, but do not loop)
-   EV::LOOP_NONBLOCK  do not block at all (fetch/handle events but do not wait)
+   EV::RUN_NOWAIT  do not block at all (fetch/handle events but do not wait)
-=item EV::unloop [$how]
+=item EV::break [$how]
+=item $loop->break ([$how])
-When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
+When called with no arguments or an argument of EV::BREAK_ONE, makes the
-innermost call to EV::loop return.
+innermost call to EV::run return.
-When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
+When called with an argument of EV::BREAK_ALL, all calls to EV::run will
-fast as possible.
+return as fast as possible.
-=item $count = EV::loop_count
+When called with an argument of EV::BREAK_CANCEL, any pending break will
+be cancelled.
+=item $count = EV::iteration
+=item $count = $loop->iteration
 Return the number of times the event loop has polled for new
-events. Sometiems useful as a generation counter.
+events. Sometimes useful as a generation counter.
 =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
+=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
 This function rolls together an I/O and a timer watcher for a single
 one-shot event without the need for managing a watcher object.
 If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
 | EV::WRITE>, indicating the type of I/O event you want to wait for. If
 you do not want to wait for some I/O event, specify C<undef> for
 C<$fh_or_undef> and C<0> for C<$events>).
 If timeout is C<undef> or negative, then there will be no
-timeout. Otherwise a EV::timer with this value will be started.
+timeout. Otherwise an C<EV::timer> with this value will be started.
 When an error occurs or either the timeout or I/O watcher triggers, then
 the callback will be called with the received event set (in general
-you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
+you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
-C<EV::WRITE> and C<EV::TIMEOUT>).
+C<EV::WRITE> and C<EV::TIMER>).
 EV::once doesn't return anything: the watchers stay active till either
 of them triggers, then they will be stopped and freed, and the callback
 invoked.
-=item EV::feed_fd_event ($fd, $revents)
+=item EV::feed_fd_event $fd, $revents
+=item $loop->feed_fd_event ($fd, $revents)
 Feed an event on a file descriptor into EV. EV will react to this call as
 if the readyness notifications specified by C<$revents> (a combination of
 C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
-=item EV::feed_signal_event ($signal)
+=item EV::feed_signal_event $signal
-Feed a signal event into EV. EV will react to this call as if the signal
+Feed a signal event into the default loop. EV will react to this call as
-specified by C<$signal> had occured.
+if the signal specified by C<$signal> had occured.
-=back
+=item EV::feed_signal $signal
+Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
+regardless of which loop has registered the signal, and is mainly useful
+for custom signal implementations.
+=item EV::set_io_collect_interval $time
+=item $loop->set_io_collect_interval ($time)
+=item EV::set_timeout_collect_interval $time
+=item $loop->set_timeout_collect_interval ($time)
+These advanced functions set the minimum block interval when polling for I/O events and the minimum
+wait interval for timer events. See the libev documentation at
+L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
+(locally installed as F<EV::libev>) for a more detailed discussion.
+=item $count = EV::pending_count
+=item $count = $loop->pending_count
+Returns the number of currently pending watchers.
+=item EV::invoke_pending
+=item $loop->invoke_pending
+Invoke all currently pending watchers.
+=back
-=head2 WATCHER OBJECTS
+=head1 WATCHER OBJECTS
 A watcher is an object that gets created to record your interest in some
 event. For instance, if you want to wait for STDIN to become readable, you
 would create an EV::io watcher for that:
-  my $watcher = EV::io *STDIN, EV::READ, sub {
+   my $watcher = EV::io *STDIN, EV::READ, sub {
-     my ($watcher, $revents) = @_;
+      my ($watcher, $revents) = @_;
-     warn "yeah, STDIN should not be readable without blocking!\n"
+      warn "yeah, STDIN should now be readable without blocking!\n"
-  };
+   };
 All watchers can be active (waiting for events) or inactive (paused). Only
 active watchers will have their callbacks invoked. All callbacks will be
 called with at least two arguments: the watcher and a bitmask of received
 events.
 Each watcher type has its associated bit in revents, so you can use the
 same callback for multiple watchers. The event mask is named after the
-type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
+type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
 EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
-(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
+(which can set both EV::READ and EV::WRITE bits).
-uses EV::TIMEOUT).
 In the rare case where one wants to create a watcher but not start it at
 the same time, each constructor has a variant with a trailing C<_ns> in
 its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
 Feed some events on this watcher into EV. EV will react to this call as if
 the watcher had received the given C<$revents> mask.
 =item $revents = $w->clear_pending
-If the watcher is pending, this function returns clears its pending status
+If the watcher is pending, this function clears its pending status and
-and returns its C<$revents> bitset (as if its callback was invoked). If the
+returns its C<$revents> bitset (as if its callback was invoked). If the
 watcher isn't pending it does nothing and returns C<0>.
 =item $previous_state = $w->keepalive ($bool)
-Normally, C<EV::loop> will return when there are no active watchers
+Normally, C<EV::run> will return when there are no active watchers
 (which is a "deadlock" because no progress can be made anymore). This is
-convinient because it allows you to start your watchers (and your jobs),
+convenient because it allows you to start your watchers (and your jobs),
-call C<EV::loop> once and when it returns you know that all your jobs are
+call C<EV::run> once and when it returns you know that all your jobs are
 finished (or they forgot to register some watchers for their task :).
-Sometimes, however, this gets in your way, for example when you the module
+Sometimes, however, this gets in your way, for example when the module
-that calls C<EV::loop> (usually the main program) is not the same module
+that calls C<EV::run> (usually the main program) is not the same module
 as a long-living watcher (for example a DNS client module written by
 somebody else even). Then you might want any outstanding requests to be
-handled, but you would not want to keep C<EV::loop> from returning just
+handled, but you would not want to keep C<EV::run> from returning just
 because you happen to have this long-running UDP port watcher.
 In this case you can clear the keepalive status, which means that even
-though your watcher is active, it won't keep C<EV::loop> from returning.
+though your watcher is active, it won't keep C<EV::run> from returning.
-The initial value for keepalive is true (enabled), and you cna change it
+The initial value for keepalive is true (enabled), and you can change it
 any time.
 Example: Register an I/O watcher for some UDP socket but do not keep the
 event loop from running just because of that watcher.
    my $udp_socket = ...
    my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
    $udp_watcher->keepalive (0);
-=back
+=item $loop = $w->loop
+Return the loop that this watcher is attached to.
+=back
-=head2 WATCHER TYPES
+=head1 WATCHER TYPES
 Each of the following subsections describes a single watcher type.
 =head3 I/O WATCHERS - is this file descriptor readable or writable?
 =over 4
 =item $w = EV::io $fileno_or_fh, $eventmask, $callback
 =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
+=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
+=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
 As long as the returned watcher object is alive, call the C<$callback>
 when at least one of events specified in C<$eventmask> occurs.
 The $eventmask can be one or more of these constants ORed together:
 =item $w = EV::timer $after, $repeat, $callback
 =item $w = EV::timer_ns $after, $repeat, $callback
+=item $w = $loop->timer ($after, $repeat, $callback)
+=item $w = $loop->timer_ns ($after, $repeat, $callback)
-Calls the callback after C<$after> seconds (which may be fractional). If
+Calls the callback after C<$after> seconds (which may be fractional or
-C<$repeat> is non-zero, the timer will be restarted (with the $repeat
+negative). If C<$repeat> is non-zero, the timer will be restarted (with
-value as $after) after the callback returns.
+the $repeat value as $after) after the callback returns.
 This means that the callback would be called roughly after C<$after>
 seconds, and then every C<$repeat> seconds. The timer does his best not
 to drift, but it will not invoke the timer more often then once per event
 loop iteration, and might drift in other cases. If that isn't acceptable,
 in front of the machine while the timer is running and changes the system
 clock, the timer will nevertheless run (roughly) the same time.
 The C<timer_ns> variant doesn't start (activate) the newly created watcher.
-=item $w->set ($after, $repeat)
+=item $w->set ($after, $repeat = 0)
 Reconfigures the watcher, see the constructor above for details. Can be called at
 any time.
 =item $w->again
+=item $w->again ($repeat)
 Similar to the C<start> method, but has special semantics for repeating timers:
 If the timer is active and non-repeating, it will be stopped.
 This behaviour is useful when you have a timeout for some IO
 operation. You create a timer object with the same value for C<$after> and
 C<$repeat>, and then, in the read/write watcher, run the C<again> method
 on the timeout.
+If called with a C<$repeat> argument, then it uses this a timer repeat
+value.
+=item $after = $w->remaining
+Calculates and returns the remaining time till the timer will fire.
+=item $old_repeat = $w->reapat ([$new_repeat])
+Returns the current value of the repeat attribute and optionally sets a
+new one. Setting the new one will not restart the watcher - if the watcher
+is active, the new repeat value is used whenever it expires next.
 =back
 =head3 PERIODIC WATCHERS - to cron or not to cron?
 =over 4
 =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
 =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
+=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
+=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
 Similar to EV::timer, but is not based on relative timeouts but on
 absolute times. Apart from creating "simple" timers that trigger "at" the
 specified time, it can also be used for non-drifting absolute timers and
 more complex, cron-like, setups that are not adversely affected by time
 This time simply fires at the wallclock time C<$at> and doesn't repeat. It
 will not adjust when a time jump occurs, that is, if it is to be run
 at January 1st 2011 then it will run when the system time reaches or
 surpasses this time.
-=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
+=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
 In this mode the watcher will always be scheduled to time out at the
-next C<$at + N * $interval> time (for some integer N) and then repeat,
+next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
-regardless of any time jumps.
+regardless of any time jumps. Note that, since C<N> can be negative, the
+first trigger can happen before C<$at>.
 This can be used to create timers that do not drift with respect to system
 time:
    my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
 That doesn't mean there will always be 3600 seconds in between triggers,
-but only that the the clalback will be called when the system time shows a
+but only that the the callback will be called when the system time shows a
 full hour (UTC).
 Another way to think about it (for the mathematically inclined) is that
 EV::periodic will try to run the callback in this mode at the next
 possible time where C<$time = $at (mod $interval)>, regardless of any time
 time the periodic watcher gets scheduled, the reschedule callback
 ($reschedule_cb) will be called with the watcher as first, and the current
 time as second argument.
 I<This callback MUST NOT stop or destroy this or any other periodic
-watcher, ever>. If you need to stop it, return 1e30 and stop it
+watcher, ever, and MUST NOT call any event loop functions or methods>. If
-afterwards.
+you need to stop it, return 1e30 and stop it afterwards. You may create
+and start an C<EV::prepare> watcher for this task.
 It must return the next time to trigger, based on the passed time value
-(that is, the lowest time value larger than to the second argument). It
+(that is, the lowest time value larger than or equal to to the second
-will usually be called just before the callback will be triggered, but
+argument). It will usually be called just before the callback will be
-might be called at other times, too.
+triggered, but might be called at other times, too.
 This can be used to create very complex timers, such as a timer that
-triggers on each midnight, local time (actually 24 hours after the last
+triggers on each midnight, local time (actually one day after the last
-midnight, to keep the example simple. If you know a way to do it correctly
+midnight, to keep the example simple):
-in about the same space (without requiring elaborate modules), drop me a
-note :):
    my $daily = EV::periodic 0, 0, sub {
       my ($w, $now) = @_;
       use Time::Local ();
       my (undef, undef, undef, $d, $m, $y) = localtime $now;
-      86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
+      Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
    }, sub {
       print "it's midnight or likely shortly after, now\n";
    };
 =back
 =item $time = $w->at
 Return the time that the watcher is expected to trigger next.
+=item $old_offset = $w->offset ([$new_offset])
+Returns the current value of the offset attribute and optionally sets a
+new one. Setting the new one will not restart the watcher - if the watcher
+is active, the new offset value is used whenever it expires next.
+=item $old_interval = $w->interval ([$new_interval])
+See above, for the interval attribute.
+=item $old_reschedule_cb = $w->reschedule_cb ([$new_reschedule_xcb])
+See above, for the reschedule callback.
 =back
 =head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
 =over 4
 =item $w = EV::signal $signal, $callback
 =item $w = EV::signal_ns $signal, $callback
+=item $w = $loop->signal ($signal, $callback)
+=item $w = $loop->signal_ns ($signal, $callback)
 Call the callback when $signal is received (the signal can be specified by
 number or by name, just as with C<kill> or C<%SIG>).
+Only one event loop can grab a given signal - attempting to grab the same
+signal from two EV loops will crash the program immediately or cause data
+corruption.
 EV will grab the signal for the process (the kernel only allows one
 component to receive a signal at a time) when you start a signal watcher,
 and removes it again when you stop it. Perl does the same when you
 add/remove callbacks to C<%SIG>, so watch out.
 =head3 CHILD WATCHERS - watch out for process status changes
 =over 4
-=item $w = EV::child $pid, $callback
+=item $w = EV::child $pid, $trace, $callback
-=item $w = EV::child_ns $pid, $callback
+=item $w = EV::child_ns $pid, $trace, $callback
+=item $w = $loop->child ($pid, $trace, $callback)
+=item $w = $loop->child_ns ($pid, $trace, $callback)
-Call the callback when a status change for pid C<$pid> (or any pid if
+Call the callback when a status change for pid C<$pid> (or any pid
-C<$pid> is 0) has been received. More precisely: when the process receives
+if C<$pid> is 0) has been received (a status change happens when the
+process terminates or is killed, or, when trace is true, additionally when
+it is stopped or continued). More precisely: when the process receives
 a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
 changed/zombie children and call the callback.
 It is valid (and fully supported) to install a child watcher after a child
 has exited but before the event loop has started its next iteration (for
 You can have as many pid watchers per pid as you want, they will all be
 called.
 The C<child_ns> variant doesn't start (activate) the newly created watcher.
-=item $w->set ($pid)
+=item $w->set ($pid, $trace)
 Reconfigures the watcher, see the constructor above for details. Can be called at
 any time.
 =item $current_pid = $w->pid
-=item $old_pid = $w->pid ($new_pid)
 Returns the previously set process id and optionally set a new one.
 =item $exit_status = $w->rstatus
 Return the exit/wait status (as returned by waitpid, see the waitpid entry
 =over 4
 =item $w = EV::stat $path, $interval, $callback
 =item $w = EV::stat_ns $path, $interval, $callback
+=item $w = $loop->stat ($path, $interval, $callback)
+=item $w = $loop->stat_ns ($path, $interval, $callback)
 Call the callback when a file status change has been detected on
 C<$path>. The C<$path> does not need to exist, changing from "path exists"
 to "path does not exist" is a status change like any other.
 =over 4
 =item $w = EV::idle $callback
 =item $w = EV::idle_ns $callback
+=item $w = $loop->idle ($callback)
+=item $w = $loop->idle_ns ($callback)
 Call the callback when there are no other pending watchers of the same or
 higher priority (excluding check, prepare and other idle watchers of the
 same or lower priority, of course). They are called idle watchers because
 when the watcher is the highest priority pending event in the process, the
 =item $w = EV::prepare $callback
 =item $w = EV::prepare_ns $callback
+=item $w = $loop->prepare ($callback)
+=item $w = $loop->prepare_ns ($callback)
 Call the callback just before the process would block. You can still
 create/modify any watchers at this point.
 See the EV::check watcher, below, for explanations and an example.
 =item $w = EV::check $callback
 =item $w = EV::check_ns $callback
+=item $w = $loop->check ($callback)
+=item $w = $loop->check_ns ($callback)
 Call the callback just after the process wakes up again (after it has
 gathered events), but before any other callbacks have been invoked.
-This is used to integrate other event-based software into the EV
+This can be used to integrate other event-based software into the EV
 mainloop: You register a prepare callback and in there, you create io and
 timer watchers as required by the other software. Here is a real-world
 example of integrating Net::SNMP (with some details left out):
    our @snmp_watcher;
       # make the dispatcher handle any new stuff
       ... not shown
    };
 The callbacks of the created watchers will not be called as the watchers
-are destroyed before this cna happen (remember EV::check gets called
+are destroyed before this can happen (remember EV::check gets called
 first).
 The C<check_ns> variant doesn't start (activate) the newly created watcher.
+=item EV::CHECK constant issues
+Like all other watcher types, there is a bitmask constant for use in
+C<$revents> and other places. The C<EV::CHECK> is special as it has
+the same name as the C<CHECK> sub called by Perl. This doesn't cause
+big issues on newer perls (beginning with 5.8.9), but it means thatthe
+constant must be I<inlined>, i.e. runtime calls will not work. That means
+that as long as you always C<use EV> and then C<EV::CHECK> you are on the
+safe side.
 =back
 =head3 FORK WATCHERS - the audacity to resume the event loop after a fork
 =item $w = EV::fork $callback
 =item $w = EV::fork_ns $callback
+=item $w = $loop->fork ($callback)
+=item $w = $loop->fork_ns ($callback)
 Call the callback before the event loop is resumed in the child process
 after a fork.
 The C<fork_ns> variant doesn't start (activate) the newly created watcher.
 =back
+=head3 EMBED WATCHERS - when one backend isn't enough...
+This is a rather advanced watcher type that lets you embed one event loop
+into another (currently only IO events are supported in the embedded
+loop, other types of watchers might be handled in a delayed or incorrect
+fashion and must not be used).
+See the libev documentation at
+L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
+(locally installed as F<EV::libev>) for more details.
+In short, this watcher is most useful on BSD systems without working
+kqueue to still be able to handle a large number of sockets:
+   my $socket_loop;
+   # check wether we use SELECT or POLL _and_ KQUEUE is supported
+   if (
+     (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
+     && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
+   ) {
+     # use kqueue for sockets
+     $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
+   }
+   # use the default loop otherwise
+   $socket_loop ||= EV::default_loop;
+=over 4
+=item $w = EV::embed $otherloop[, $callback]
+=item $w = EV::embed_ns $otherloop[, $callback]
+=item $w = $loop->embed ($otherloop[, $callback])
+=item $w = $loop->embed_ns ($otherloop[, $callback])
+Call the callback when the embedded event loop (C<$otherloop>) has any
+I/O activity. The C<$callback> is optional: if it is missing, then the
+embedded event loop will be managed automatically (which is recommended),
+otherwise you have to invoke C<sweep> yourself.
+The C<embed_ns> variant doesn't start (activate) the newly created watcher.
+=back
+=head3 ASYNC WATCHERS - how to wake up another event loop
+Async watchers are provided by EV, but have little use in perl directly,
+as perl neither supports threads running in parallel nor direct access to
+signal handlers or other contexts where they could be of value.
+It is, however, possible to use them from the XS level.
+Please see the libev documentation for further details.
+=over 4
+=item $w = EV::async $callback
+=item $w = EV::async_ns $callback
+=item $w = $loop->async ($callback)
+=item $w = $loop->async_ns ($callback)
+=item $w->send
+=item $bool = $w->async_pending
+=back
+=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
+Cleanup watchers are not supported on the Perl level, they can only be
+used via XS currently.
 =head1 PERL SIGNALS
 While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
 to be called on every event loop iteration by installing a C<EV::check>
 watcher:
    my $async_check = EV::check sub { };
-This ensures that perl shortly gets into control for a short time, and
+This ensures that perl gets into control for a short time to handle any
-also ensures slower overall operation.
+pending signals, and also ensures (slightly) slower overall operation.
-=head1 THREADS
+=head1 ITHREADS
-Threads are not supported by this module in any way. Perl pseudo-threads
+Ithreads are not supported by this module in any way. Perl pseudo-threads
-is evil stuff and must die. As soon as Perl gains real threads I will work
+is evil stuff and must die. Real threads as provided by Coro are fully
-on thread support for it.
+supported (and enhanced support is available via L<Coro::EV>).
 =head1 FORK
 Most of the "improved" event delivering mechanisms of modern operating
 systems have quite a few problems with fork(2) (to put it bluntly: it is
 1;
 =head1 SEE ALSO
+L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
-L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
+(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
-event loop), L<Coro::EV> (efficient coroutines with EV).
+loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
+integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
+event-loop agnostic and portable event driven programming.
 =head1 AUTHOR
- Marc Lehmann <schmorp@schmorp.de>
+   Marc Lehmann <schmorp@schmorp.de>
- http://home.schmorp.de/
+   http://home.schmorp.de/
 =cut

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Revision 1.162 by root, Wed Jan 22 23:17:31 2020 UTC