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

Comparing EV/EV.pm (file contents):
Revision 1.102 by root, Mon Sep 8 17:27:42 2008 UTC vs.
Revision 1.129 by root, Thu Oct 21 15:13:42 2010 UTC

    # MAINLOOP
    EV::loop;           # loop until EV::unloop is called or all watchers stop
    EV::loop EV::LOOP_ONESHOT;  # block until at least one event could be handled
    EV::loop EV::LOOP_NONBLOCK; # 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://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more
+libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
-subtle details on watcher semantics or some discussion on the available
+F<perldoc EV::libev>) for more subtle details on watcher semantics or some
-backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just
+discussion on the available backends, or how to force a specific backend
-about in any case 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;
-no warnings;
+use common::sense;
-use strict;
 BEGIN {
-   our $VERSION = '3.44';
+   our $VERSION = '4.00';
    use XSLoader;
    XSLoader::load "EV", $VERSION;
 }
 @EV::IO::ISA       =
 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 avdantage of kqueue (which often works properly for
+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]
+=item $loop = new EV::Loop [$flags]
-Create a new event loop as per the specified flags. Please refer to the
+Create a new event loop as per the specified flags. Please refer to
-C<ev_loop_new ()> function description in the libev documentation
+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>)
+(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
-for more info.
+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.
-Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
+If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
-is protected by this module.
+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
 =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 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::loop>.
+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 $loop->loop ([$flags])
 =item $count = EV::loop_count
 =item $count = $loop->loop_count
 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))
 timeout. Otherwise a 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>,
-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 $loop->set_timeout_collect_interval ($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> for
+L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
-a more detailed discussion.
+(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
 =head1 WATCHER OBJECTS
 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.
 =item $previous_state = $w->keepalive ($bool)
 Normally, C<EV::loop> 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
 finished (or they forgot to register some watchers for their task :).
 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
 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.
-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.
 =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.
 =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
 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_>
-for more details.
+(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;
 =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
+Async watchers are provided by EV, but have little use in perl directly,
-neither supports threads nor direct access to signal handlers or other
+as perl neither supports threads running in parallel nor direct access to
-contexts where they could be of value.
+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.
    my $async_check = EV::check sub { };
 This ensures that perl gets into control for a short time to handle any
 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

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Comparing EV/EV.pm (file contents): Revision 1.102 by root, Mon Sep 8 17:27:42 2008 UTC vs. Revision 1.129 by root, Thu Oct 21 15:13:42 2010 UTC

Diff Legend

Comparing EV/EV.pm (file contents):
Revision 1.102 by root, Mon Sep 8 17:27:42 2008 UTC vs.
Revision 1.129 by root, Thu Oct 21 15:13:42 2010 UTC