[ViewVC] Diff of: cvs/EV/README

Comparing EV/README (file contents):
Revision 1.34 by root, Sun Aug 9 13:30:41 2009 UTC vs.
Revision 1.49 by root, Thu Oct 19 17:22:50 2023 UTC

           my ($w, $revents) = @_;
           warn $w->path, " has changed somehow.\n";
        };
        # 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
+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 AnyEvent instead,
+    specifically the simplified API described in AE.
+    When used with EV as backend, the AE API is as fast as the native EV
+    API, but your programs/modules will still run with many other event
+    loops.
 DESCRIPTION
     This module provides an interface to libev
     (<http://software.schmorp.de/pkg/libev.html>). While the documentation
     below is comprehensive, one might also consult the documentation of
     can use it through the 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.
+  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.
   MODULE EXPORTS
     This module does not export any symbols.
 EVENT LOOPS
     EV supports multiple event loops: There is a single "default event loop"
         Must be called after a fork in the child, before entering or
         continuing the event loop. An alternative is to use
         "EV::FLAG_FORKCHECK" which calls this function automatically, at
         some performance loss (refer to the libev documentation).
-    $loop->loop_verify
+    $loop->verify
         Calls "ev_verify" to make internal consistency checks (for debugging
         libev) and abort the program if any data structures were found to be
         corrupted.
     $loop = EV::default_loop [$flags]
     EV::now_update
     $loop->now_update
         Establishes the current time by querying the kernel, updating the
         time returned by "EV::now" in the progress. This is a costly
-        operation and is usually done automatically within "EV::loop".
+        operation and is usually done automatically within "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.
     $backend = EV::backend
     $backend = $loop->backend
         Returns an integer describing the backend used by libev
         (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
-    EV::loop [$flags]
+    $active = EV::run [$flags]
-    $loop->loop ([$flags])
+    $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 $flags argument can be one of the following:
-           0                  as above
+           0               as above
-           EV::LOOP_ONESHOT   block at most once (wait, but do not loop)
+           EV::RUN_ONCE    block at most once (wait, but do not loop)
-           EV::LOOP_NONBLOCK  do not block at all (fetch/handle events but do not wait)
+           EV::RUN_NOWAIT  do not block at all (fetch/handle events but do not wait)
-    EV::unloop [$how]
+    EV::break [$how]
-    $loop->unloop ([$how])
+    $loop->break ([$how])
-        When called with no arguments or an argument of EV::UNLOOP_ONE,
+        When called with no arguments or an argument of EV::BREAK_ONE, makes
-        makes the innermost call to EV::loop return.
+        the innermost call to EV::run return.
-        When called with an argument of EV::UNLOOP_ALL, all calls to
+        When called with an argument of EV::BREAK_ALL, all calls to EV::run
-        EV::loop will return as fast as possible.
+        will return as fast as possible.
-    $count = EV::loop_count
+        When called with an argument of EV::BREAK_CANCEL, any pending break
-    $count = $loop->loop_count
+        will be cancelled.
+    $count = EV::iteration
+    $count = $loop->iteration
         Return the number of times the event loop has polled for new events.
         Sometimes useful as a generation counter.
     EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
     $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
         "EV::READ | 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
         "undef" for $fh_or_undef and 0 for $events).
         If timeout is "undef" or negative, then there will be no timeout.
-        Otherwise a EV::timer with this value will be started.
+        Otherwise an "EV::timer" with this value will be started.
         When an error occurs or either the timeout or I/O watcher triggers,
         then the callback will be called with the received event set (in
         general you can expect it to be a combination of "EV::ERROR",
-        "EV::READ", "EV::WRITE" and "EV::TIMEOUT").
+        "EV::READ", "EV::WRITE" and "EV::TIMER").
         EV::once doesn't return anything: the watchers stay active till
         either of them triggers, then they will be stopped and freed, and
         the callback invoked.
-    EV::feed_fd_event ($fd, $revents)
+    EV::feed_fd_event $fd, $revents
     $loop->feed_fd_event ($fd, $revents)
         Feed an event on a file descriptor into EV. EV will react to this
         call as if the readyness notifications specified by $revents (a
         combination of "EV::READ" and "EV::WRITE") happened on the file
         descriptor $fd.
-    EV::feed_signal_event ($signal)
+    EV::feed_signal_event $signal
-        Feed a signal event into EV. EV will react to this call as if the
+        Feed a signal event into the default loop. EV will react to this
-        signal specified by $signal had occured.
+        call as if the signal specified by $signal had occured.
+    EV::feed_signal $signal
+        Feed a signal event into EV - unlike "EV::feed_signal_event", this
+        works regardless of which loop has registered the signal, and is
+        mainly useful for custom signal implementations.
     EV::set_io_collect_interval $time
     $loop->set_io_collect_interval ($time)
     EV::set_timeout_collect_interval $time
     $loop->set_timeout_collect_interval ($time)
     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,
     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
+    events (which can set both EV::READ and EV::WRITE bits).
-    (which 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 "_ns" in
     its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
         If the watcher is pending, this function clears its pending status
         and returns its $revents bitset (as if its callback was invoked). If
         the watcher isn't pending it does nothing and returns 0.
     $previous_state = $w->keepalive ($bool)
-        Normally, "EV::loop" will return when there are no active watchers
+        Normally, "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
+        This is convenient because it allows you to start your watchers (and
-        your jobs), call "EV::loop" once and when it returns you know that
+        your jobs), call "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 the
-        module that calls "EV::loop" (usually the main program) is not the
+        module that calls "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
-        "EV::loop" from returning just because you happen to have this
+        "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 "EV::loop" from
+        even though your watcher is active, it won't keep "EV::run" from
         returning.
         The initial value for keepalive is true (enabled), and you can
         change it any time.
    TIMER WATCHERS - relative and optionally repeating timeouts
     $w = EV::timer $after, $repeat, $callback
     $w = EV::timer_ns $after, $repeat, $callback
     $w = $loop->timer ($after, $repeat, $callback)
     $w = $loop->timer_ns ($after, $repeat, $callback)
-        Calls the callback after $after seconds (which may be fractional).
+        Calls the callback after $after seconds (which may be fractional or
-        If $repeat is non-zero, the timer will be restarted (with the
+        negative). If $repeat is non-zero, the timer will be restarted (with
-        $repeat 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 $after
         seconds, and then every $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
         the same time.
         The "timer_ns" variant doesn't start (activate) the newly created
         watcher.
-    $w->set ($after, $repeat)
+    $w->set ($after, $repeat = 0)
         Reconfigures the watcher, see the constructor above for details. Can
         be called at any time.
     $w->again
+    $w->again ($repeat)
         Similar to the "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 $after
         and $repeat, and then, in the read/write watcher, run the "again"
         method on the timeout.
+        If called with a $repeat argument, then it uses this a timer repeat
+        value.
+    $after = $w->remaining
+        Calculates and returns the remaining time till the timer will fire.
+    $repeat = $w->repeat
+    $old_repeat = $w->repeat ($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.
    PERIODIC WATCHERS - to cron or not to cron?
     $w = EV::periodic $at, $interval, $reschedule_cb, $callback
     $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
     $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
             system time reaches or surpasses this time.
         *   repeating interval timer ($interval > 0, $reschedule_cb = 0)
             In this mode the watcher will always be scheduled to time out at
-            the next "$at + N * $interval" time (for some integer N) and
+            the next "$at + N * $interval" time (for the lowest integer N)
-            then repeat, regardless of any time jumps.
+            and then repeat, regardless of any time jumps. Note that, since
+            "N" can be negative, the first trigger can happen before $at.
             This can be used to create timers that do not drift with respect
             to system time:
                my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
             That doesn't mean there will always be 3600 seconds in between
-            triggers, but only that the the clalback will be called when the
+            triggers, but only that the the callback will be called when the
             system time shows a full hour (UTC).
             Another way to think about it (for the mathematically inclined)
             is that EV::periodic will try to run the callback in this mode
             at the next possible time where "$time = $at (mod $interval)",
             first, and the current time as second argument.
             *This callback MUST NOT stop or destroy this or any other
             periodic watcher, ever, and MUST NOT call any event loop
             functions or methods*. If you need to stop it, return 1e30 and
-            stop it afterwards. You may create and start a "EV::prepare"
+            stop it afterwards. You may create and start an "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 or equal
             to to the second argument). It will usually be called just
             before the callback will be 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
+            that triggers on each midnight, local time (actually one day
-            after the last midnight, to keep the example simple. If you know
+            after the last midnight, to keep the example simple):
-            a way to do it correctly 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";
                };
         The "periodic_ns" variant doesn't start (activate) the newly created
     $w->again
         Simply stops and starts the watcher again.
     $time = $w->at
         Return the time that the watcher is expected to trigger next.
+    $offset = $w->offset
+    $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.
+    $interval = $w->interval
+    $old_interval = $w->interval ($new_interval)
+        See above, for the interval attribute.
+    $reschedule_cb = $w->reschedule_cb
+    $old_reschedule_cb = $w->reschedule_cb ($new_reschedule_cb)
+        See above, for the reschedule callback.
    SIGNAL WATCHERS - signal me when a signal gets signalled!
     $w = EV::signal $signal, $callback
     $w = EV::signal_ns $signal, $callback
     $w = $loop->signal ($signal, $callback)
     $pid = $w->rpid
         Return the pid of the awaited child (useful when you have installed
         a watcher for all pids).
+    EV::Child::reinit [EXPERIMENTAL]
+        Internally, libev installs a signal handler for "SIGCHLD".
+        Unfortunately, a lot of Perl code does soemthing like "local
+        $SIG{CHLD}", which, unfortunately, is broken and will not restore
+        the signal handler.
+        If this has happened, you can call this function to stop/rrestart
+        the internal libev watcher, which will reset the signal handler.
+        Note that this is an experimental function, whose interface might
+        change.
    STAT WATCHERS - did the file attributes just change?
     $w = EV::stat $path, $interval, $callback
     $w = EV::stat_ns $path, $interval, $callback
     $w = $loop->stat ($path, $interval, $callback)
     $w = $loop->stat_ns ($path, $interval, $callback)
     $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):
         watchers are destroyed before this can happen (remember EV::check
         gets called first).
         The "check_ns" variant doesn't start (activate) the newly created
         watcher.
+    EV::CHECK constant issues
+        Like all other watcher types, there is a bitmask constant for use in
+        $revents and other places. The "EV::CHECK" is special as it has the
+        same name as the "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 *inlined*, i.e. runtime calls will not work. That
+        means that as long as you always "use EV" and then "EV::CHECK" you
+        are on the safe side.
    FORK WATCHERS - the audacity to resume the event loop after a fork
     Fork watchers are called when a "fork ()" was detected. The invocation
     is done before the event loop blocks next and before "check" watchers
     are being called, and only in the child after the fork.
     Please see the libev documentation for further details.
     $w = EV::async $callback
     $w = EV::async_ns $callback
+    $w = $loop->async ($callback)
+    $w = $loop->async_ns ($callback)
     $w->send
     $bool = $w->async_pending
+   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.
 PERL SIGNALS
     While Perl signal handling (%SIG) is not affected by EV, the behaviour
     with EV is as the same as any other C library: Perl-signals will only be
     handled when Perl runs, which means your signal handler might be invoked
     On win32, there is no notion of fork so all this doesn't apply, of
     course.
 SEE ALSO
-    EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
+    EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous
-    loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
+    DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed
-    with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
+    Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV
-    agnostic and portable event driven programming.
+    (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event
+    driven programming.
 AUTHOR
        Marc Lehmann <schmorp@schmorp.de>
        http://home.schmorp.de/

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Comparing EV/README (file contents): Revision 1.34 by root, Sun Aug 9 13:30:41 2009 UTC vs. Revision 1.49 by root, Thu Oct 19 17:22:50 2023 UTC

Diff Legend

Comparing EV/README (file contents):
Revision 1.34 by root, Sun Aug 9 13:30:41 2009 UTC vs.
Revision 1.49 by root, Thu Oct 19 17:22:50 2023 UTC