[ViewVC] Diff of: cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.334 by root, Mon Oct 25 10:30:23 2010 UTC vs.
Revision 1.337 by root, Sun Oct 31 20:20:20 2010 UTC

 epoll scales either O(1) or O(active_fds).
 The epoll mechanism deserves honorable mention as the most misdesigned
 of the more advanced event mechanisms: mere annoyances include silently
 dropping file descriptors, requiring a system call per change per file
-descriptor (and unnecessary guessing of parameters), problems with dup and
+descriptor (and unnecessary guessing of parameters), problems with dup,
+returning before the timeout value requiring additional iterations and so
-so on. The biggest issue is fork races, however - if a program forks then
+on. The biggest issue is fork races, however - if a program forks then
 I<both> parent and child process have to recreate the epoll set, which can
 take considerable time (one syscall per file descriptor) and is of course
 hard to detect.
 Epoll is also notoriously buggy - embedding epoll fds I<should> work, but
 Can be used to make a call to C<ev_run> return early (but only after it
 has processed all outstanding events). The C<how> argument must be either
 C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
 C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
-This "unloop state" will be cleared when entering C<ev_run> again.
+This "break state" will be cleared when entering C<ev_run> again.
-It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
+It is safe to call C<ev_break> from outside any C<ev_run> calls, too.
 =item ev_ref (loop)
 =item ev_unref (loop)
 programs, though, as the fd could already be closed and reused for another
 thing, so beware.
 =back
-=head2 WATCHER STATES
-There are various watcher states mentioned throughout this manual -
-active, pending and so on. In this section these states and the rules to
-transition between them will be described in more detail - and while these
-rules might look complicated, they usually do "the right thing".
-=over 4
-=item initialiased
-Before a watcher can be registered with the event looop it has to be
-initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
-C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
-In this state it is simply some block of memory that is suitable for use
-in an event loop. It can be moved around, freed, reused etc. at will.
-=item started/running/active
-Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
-property of the event loop, and is actively waiting for events. While in
-this state it cannot be accessed (except in a few documented ways), moved,
-freed or anything else - the only legal thing is to keep a pointer to it,
-and call libev functions on it that are documented to work on active watchers.
-=item pending
-If a watcher is active and libev determines that an event it is interested
-in has occurred (such as a timer expiring), it will become pending. It will
-stay in this pending state until either it is stopped or its callback is
-about to be invoked, so it is not normally pending inside the watcher
-callback.
-The watcher might or might not be active while it is pending (for example,
-an expired non-repeating timer can be pending but no longer active). If it
-is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
-but it is still property of the event loop at this time, so cannot be
-moved, freed or reused. And if it is active the rules described in the
-previous item still apply.
-It is also possible to feed an event on a watcher that is not active (e.g.
-via C<ev_feed_event>), in which case it becomes pending without being
-active.
-=item stopped
-A watcher can be stopped implicitly by libev (in which case it might still
-be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
-latter will clear any pending state the watcher might be in, regardless
-of whether it was active or not, so stopping a watcher explicitly before
-freeing it is often a good idea.
-While stopped (and not pending) the watcher is essentially in the
-initialised state, that is it can be reused, moved, modified in any way
-you wish.
-=back
 =head2 GENERIC WATCHER FUNCTIONS
 =over 4
 =item C<ev_init> (ev_TYPE *watcher, callback)
 See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
 functions that do not need a watcher.
 =back
 =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
 Each watcher has, by default, a member C<void *data> that you can change
 and read at any time: libev will completely ignore it. This can be used
    t2_cb (EV_P_ ev_timer *w, int revents)
    {
      struct my_biggy big = (struct my_biggy *)
        (((char *)w) - offsetof (struct my_biggy, t2));
    }
+=head2 WATCHER STATES
+There are various watcher states mentioned throughout this manual -
+active, pending and so on. In this section these states and the rules to
+transition between them will be described in more detail - and while these
+rules might look complicated, they usually do "the right thing".
+=over 4
+=item initialiased
+Before a watcher can be registered with the event looop it has to be
+initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
+C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
+In this state it is simply some block of memory that is suitable for use
+in an event loop. It can be moved around, freed, reused etc. at will.
+=item started/running/active
+Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
+property of the event loop, and is actively waiting for events. While in
+this state it cannot be accessed (except in a few documented ways), moved,
+freed or anything else - the only legal thing is to keep a pointer to it,
+and call libev functions on it that are documented to work on active watchers.
+=item pending
+If a watcher is active and libev determines that an event it is interested
+in has occurred (such as a timer expiring), it will become pending. It will
+stay in this pending state until either it is stopped or its callback is
+about to be invoked, so it is not normally pending inside the watcher
+callback.
+The watcher might or might not be active while it is pending (for example,
+an expired non-repeating timer can be pending but no longer active). If it
+is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
+but it is still property of the event loop at this time, so cannot be
+moved, freed or reused. And if it is active the rules described in the
+previous item still apply.
+It is also possible to feed an event on a watcher that is not active (e.g.
+via C<ev_feed_event>), in which case it becomes pending without being
+active.
+=item stopped
+A watcher can be stopped implicitly by libev (in which case it might still
+be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
+latter will clear any pending state the watcher might be in, regardless
+of whether it was active or not, so stopping a watcher explicitly before
+freeing it is often a good idea.
+While stopped (and not pending) the watcher is essentially in the
+initialised state, that is it can be reused, moved, modified in any way
+you wish.
+=back
 =head2 WATCHER PRIORITY MODELS
 Many event loops support I<watcher priorities>, which are usually small
 integers that influence the ordering of event callback invocation

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Comparing libev/ev.pod (file contents): Revision 1.334 by root, Mon Oct 25 10:30:23 2010 UTC vs. Revision 1.337 by root, Sun Oct 31 20:20:20 2010 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.334 by root, Mon Oct 25 10:30:23 2010 UTC vs.
Revision 1.337 by root, Sun Oct 31 20:20:20 2010 UTC