[ViewVC] Diff of: cvs/EV/README

Comparing EV/README (file contents):
Revision 1.22 by root, Mon Jan 28 12:24:05 2008 UTC vs.
Revision 1.36 by root, Thu Oct 21 02:46:59 2010 UTC

 NAME
     EV - perl interface to libev, a high performance full-featured event
     loop
 SYNOPSIS
-      use EV;
+       use EV;
-  # TIMERS
+       # TIMERS
-  my $w = EV::timer 2, 0, sub {
+       my $w = EV::timer 2, 0, sub {
-         warn "is called after 2s";
+          warn "is called after 2s";
-      };
+       };
-  my $w = EV::timer 2, 2, sub {
+       my $w = EV::timer 2, 2, sub {
-         warn "is called roughly every 2s (repeat = 2)";
+          warn "is called roughly every 2s (repeat = 2)";
-      };
+       };
-  undef $w; # destroy event watcher again
+       undef $w; # destroy event watcher again
-  my $w = EV::periodic 0, 60, 0, sub {
+       my $w = EV::periodic 0, 60, 0, sub {
-         warn "is called every minute, on the minute, exactly";
+          warn "is called every minute, on the minute, exactly";
-      };
+       };
-  # IO
+       # IO
-  my $w = EV::io *STDIN, EV::READ, sub {
+       my $w = EV::io *STDIN, EV::READ, sub {
-         my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
+          my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
-         warn "stdin is readable, you entered: ", <STDIN>;
+          warn "stdin is readable, you entered: ", <STDIN>;
-      };
+       };
-  # SIGNALS
+       # SIGNALS
-  my $w = EV::signal 'QUIT', sub {
+       my $w = EV::signal 'QUIT', sub {
-         warn "sigquit received\n";
+          warn "sigquit received\n";
-      };
+       };
-  # CHILD/PID STATUS CHANGES
+       # CHILD/PID STATUS CHANGES
-      my $w = EV::child 666, 0, sub {
+       my $w = EV::child 666, 0, sub {
-         my ($w, $revents) = @_;
+          my ($w, $revents) = @_;
-         my $status = $w->rstatus;
+          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::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_ONESHOT;  # block until at least one event could be handled
-      EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
+       EV::loop EV::LOOP_NONBLOCK; # 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
-    libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle
+    libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
-    details on watcher semantics or some discussion on the available
+    perldoc EV::libev) for more subtle details on watcher semantics or some
-    backends, or how to force a specific backend with "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 "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 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.
+  MODULE EXPORTS
+    This module does not export any symbols.
 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
     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
+    *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.
-    $loop = new EV::loop [$flags]
+    $loop = new EV::Loop [$flags]
         Create a new event loop as per the specified flags. Please refer to
         the "ev_loop_new ()" function description in the libev documentation
         (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
-        ONS>) for more info.
+        ONS>, or locally-installed as 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 "EV::FLAG_FORKCHECK" is recommended, as only the default event
+        If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK"
-        loop is protected by this module.
+        is recommended, as only the default event loop is protected by this
+        module. If you *are* embedding this loop in the default loop, this
+        is not necessary, as "EV::embed" automatically does the right thing
+        on fork.
     $loop->loop_fork
         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 fucntion automatically, at
+        "EV::FLAG_FORKCHECK" which calls this function automatically, at
         some performance loss (refer to the libev documentation).
+    $loop->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]
-        Return the default loop (which is a singleton object).
+        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.
 BASIC INTERFACE
     $EV::DIED
         Must contain a reference to a function that is called when a
         callback throws an exception (with $@ containing the error). The
         Returns the current time in (fractional) seconds since the epoch.
     $time = EV::now
     $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
+        This is the time that (relative) timers are based on, and referring
         to it is usually faster then calling EV::time.
+    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".
+        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.
+    EV::suspend
+    $loop->suspend
+    EV::resume
+    $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 "^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 "suspend" in your "SIGTSTP" handler, sending
+        yourself a "SIGSTOP" and calling "resume" directly afterwards to
+        resume timer processing.
+        Effectively, all "timer" watchers will be delayed by the time spend
+        between "suspend" and "resume", and all "periodic" watchers will be
+        rescheduled (that is, they will lose any events that would have
+        occured while suspended).
+        After calling "suspend" you must not call *any* function on the
+        given loop other than "resume", and you must not call "resume"
+        without a previous call to "suspend".
+        Calling "suspend"/"resume" has the side effect of updating the event
+        loop time (see "now_update").
     $backend = EV::backend
     $backend = $loop->backend
         Returns an integer describing the backend used by libev
-        (EV::METHOD_SELECT or EV::METHOD_EPOLL).
+        (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
     EV::loop [$flags]
     $loop->loop ([$flags])
         Begin checking for events and calling callbacks. It returns when a
         callback calls EV::unloop.
         EV::loop will return as fast as possible.
     $count = EV::loop_count
     $count = $loop->loop_count
         Return the number of times the event loop has polled for new events.
-        Sometiems useful as a generation counter.
+        Sometimes useful as a generation counter.
     EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
     $loop->once ($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.
         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 "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.
     $loop->set_timeout_collect_interval ($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
         <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
-        ROLLING_THE_EVENT_LOOP> for a more detailed discussion.
+        ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
+        detailed discussion.
+    $count = EV::pending_count
+    $count = $loop->pending_count
+        Returns the number of currently pending watchers.
+    EV::invoke_pending
+    $loop->invoke_pending
+        Invoke all currently pending watchers.
 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 now 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
+    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.
         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
         (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
         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
         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
         returning.
-        The initial value for keepalive is true (enabled), and you cna
+        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 { ... };
-           $1000udp_watcher->keepalive (0);
+           $udp_watcher->keepalive (0);
     $loop = $w->loop
         Return the loop that this watcher is attached to.
 WATCHER TYPES
             This time simply fires at the wallclock time $at and doesn't
             repeat. It will not adjust when a time jump occurs, that is, if
             it is to be run at January 1st 2011 then it will run when the
             system time reaches or surpasses this time.
-        *   non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
+        *   repeating interval timer ($interval > 0, $reschedule_cb = 0)
             In this mode the watcher will always be scheduled to time out at
             the next "$at + N * $interval" time (for some integer N) and
             then repeat, regardless of any time jumps.
             each time the periodic watcher gets scheduled, the reschedule
             callback ($reschedule_cb) will be called with the watcher as
             first, and the current time as second argument.
             *This callback MUST NOT stop or destroy this or any other
+            periodic watcher, ever, and MUST NOT call any event loop
-            periodic watcher, ever*. If you need to stop it, return 1e30 and
+            functions or methods*. If you need to stop it, return 1e30 and
-            stop it afterwards.
+            stop it afterwards. You may create and start a "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
+            time value (that is, the lowest time value larger than or equal
-            second argument). It will usually be called just before the
+            to to the second argument). It will usually be called just
-            callback will be triggered, but might be called at other times,
+            before the callback will be triggered, but might be called at
-            too.
+            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 midnight, to keep the example simple. If you know
             a way to do it correctly in about the same space (without
         Return the time that the watcher is expected to trigger next.
    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)
+    $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 "kill" or %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 %SIG, so watch out.
               # 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
+        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.
     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
     <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
-    _when_one_backend_> for more details.
+    _when_one_backend_> (locally installed as 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;
+       my $socket_loop;
-      # check wether we use SELECT or POLL _and_ KQUEUE is supported
+       # check wether we use SELECT or POLL _and_ KQUEUE is supported
-      if (
+       if (
-        (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
+         (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT))
-        && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
+         && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
-      ) {
+       ) {
-        # use kqueue for sockets
+         # use kqueue for sockets
-        $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
+         $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV;
-      }
+       }
-      # use the default loop otherwise
+       # use the default loop otherwise
-      $socket_loop ||= EV::default_loop;
+       $socket_loop ||= EV::default_loop;
-    $w = EV::embed $otherloop, $callback
+    $w = EV::embed $otherloop[, $callback]
-    $w = EV::embed_ns $otherloop, $callback
+    $w = EV::embed_ns $otherloop[, $callback]
-    $w = $loop->embed ($otherloop, $callback)
+    $w = $loop->embed ($otherloop[, $callback])
-    $w = $loop->embed_ns ($otherloop, $callback)
+    $w = $loop->embed_ns ($otherloop[, $callback])
         Call the callback when the embedded event loop ($otherloop) has any
-        I/O activity. The $callback should alwas be specified as "undef" in
+        I/O activity. The $callback is optional: if it is missing, then the
-        this version of EV, which means the embedded event loop will be
+        embedded event loop will be managed automatically (which is
-        managed automatically.
+        recommended), otherwise you have to invoke "sweep" yourself.
         The "embed_ns" variant doesn't start (activate) the newly created
         watcher.
+   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.
+    $w = EV::async $callback
+    $w = EV::async_ns $callback
+    $w->send
+    $bool = $w->async_pending
 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
        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.
-THREADS
+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
-    is evil stuff and must die. As soon as Perl gains real threads I will
+    pseudo-threads is evil stuff and must die. Real threads as provided by
-    work on thread support for it.
+    Coro are fully supported (and enhanced support is available via
+    Coro::EV).
 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
     not supported and usually destructive). Libev makes it possible to work
     course.
 SEE ALSO
     EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
     loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
-    with EV), Net::SNMP::EV (asynchronous SNMP).
+    with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
+    agnostic and portable event driven programming.
 AUTHOR
-     Marc Lehmann <schmorp@schmorp.de>
+       Marc Lehmann <schmorp@schmorp.de>
-     http://home.schmorp.de/
+       http://home.schmorp.de/

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Comparing EV/README (file contents): Revision 1.22 by root, Mon Jan 28 12:24:05 2008 UTC vs. Revision 1.36 by root, Thu Oct 21 02:46:59 2010 UTC

Diff Legend

Comparing EV/README (file contents):
Revision 1.22 by root, Mon Jan 28 12:24:05 2008 UTC vs.
Revision 1.36 by root, Thu Oct 21 02:46:59 2010 UTC