[ViewVC] Diff of: cvs/AnyEvent/README

Comparing AnyEvent/README (file contents):
Revision 1.57 by root, Sat Dec 5 02:52:03 2009 UTC vs.
Revision 1.59 by root, Tue Jan 5 10:45:25 2010 UTC

        $done->recv;
   IDLE WATCHERS
        $w = AnyEvent->idle (cb => <callback>);
-    Sometimes there is a need to do something, but it is not so important to
+    Repeatedly invoke the callback after the process becomes idle, until
-    do it instantly, but only when there is nothing better to do. This
+    either the watcher is destroyed or new events have been detected.
-    "nothing better to do" is usually defined to be "no other events need
-    attention by the event loop".
-    Idle watchers ideally get invoked when the event loop has nothing better
+    Idle watchers are useful when there is a need to do something, but it is
-    to do, just before it would block the process to wait for new events.
+    not so important (or wise) to do it instantly. The callback will be
-    Instead of blocking, the idle watcher is invoked.
+    invoked only when there is "nothing better to do", which is usually
+    defined as "all outstanding events have been handled and no new events
+    have been detected". That means that idle watchers ideally get invoked
+    when the event loop has just polled for new events but none have been
+    detected. Instead of blocking to wait for more events, the idle watchers
+    will be invoked.
-    Most event loops unfortunately do not really support idle watchers (only
+    Unfortunately, most event loops do not really support idle watchers
-    EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
+    (only EV, Event and Glib do it in a usable fashion) - for the rest,
-    will simply call the callback "from time to time".
+    AnyEvent will simply call the callback "from time to time".
     Example: read lines from STDIN, but only process them when the program
     is otherwise idle:
        my @lines; # read data
         You should check $AnyEvent::MODEL before adding to this array,
         though: if it is defined then the event loop has already been
         detected, and the array will be ignored.
         Best use "AnyEvent::post_detect { BLOCK }" when your application
-        allows it,as it takes care of these details.
+        allows it, as it takes care of these details.
         This variable is mainly useful for modules that can do something
         useful when AnyEvent is used and thus want to know when it is
         initialised, but do not need to even load it by default. This array
         provides the means to hook into AnyEvent passively, without loading
         it.
+        Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
+        together, you could put this into Coro (this is the actual code used
+        by Coro to accomplish this):
+           if (defined $AnyEvent::MODEL) {
+              # AnyEvent already initialised, so load Coro::AnyEvent
+              require Coro::AnyEvent;
+           } else {
+              # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
+              # as soon as it is
+              push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
+           }
 WHAT TO DO IN A MODULE
     As a module author, you should "use AnyEvent" and call AnyEvent methods
     freely, but you should not load a specific event module or rely on it.
         additionally use it to try to use a monotonic clock for timing
         stability.
 FORK
     Most event libraries are not fork-safe. The ones who are usually are
-    because they rely on inefficient but fork-safe "select" or "poll" calls.
+    because they rely on inefficient but fork-safe "select" or "poll" calls
-    Only EV is fully fork-aware.
+    - higher performance APIs such as BSD's kqueue or the dreaded Linux
+    epoll are usually badly thought-out hacks that are incompatible with
+    fork in one way or another. Only EV is fully fork-aware and ensures that
+    you continue event-processing in both parent and child (or both, if you
+    know what you are doing).
     This means that, in general, you cannot fork and do event processing in
-    the child if a watcher was created before the fork (which in turn
+    the child if the event library was initialised before the fork (which
-    initialises the event library).
+    usually happens when the first AnyEvent watcher is created, or the
+    library is loaded).
     If you have to fork, you must either do so *before* creating your first
     watcher OR you must not use AnyEvent at all in the child OR you must do
     something completely out of the scope of AnyEvent.
     The problem of doing event processing in the parent *and* the child is
     much more complicated: even for backends that *are* fork-aware or
     fork-safe, their behaviour is not usually what you want: fork clones all
     watchers, that means all timers, I/O watchers etc. are active in both
-    parent and child, which is almost never what you want.
+    parent and child, which is almost never what you want. USing "exec" to
+    start worker children from some kind of manage rprocess is usually
+    preferred, because it is much easier and cleaner, at the expense of
+    having to have another binary.
 SECURITY CONSIDERATIONS
     AnyEvent can be forced to load any event model via
     $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used
     to execute arbitrary code or directly gain access, it can easily be used

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Comparing AnyEvent/README (file contents): Revision 1.57 by root, Sat Dec 5 02:52:03 2009 UTC vs. Revision 1.59 by root, Tue Jan 5 10:45:25 2010 UTC

Diff Legend

Comparing AnyEvent/README (file contents):
Revision 1.57 by root, Sat Dec 5 02:52:03 2009 UTC vs.
Revision 1.59 by root, Tue Jan 5 10:45:25 2010 UTC