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

Comparing libev/ev.pod (file contents):
Revision 1.18 by root, Mon Nov 12 09:01:12 2007 UTC vs.
Revision 1.27 by root, Wed Nov 14 05:02:07 2007 UTC

 =over 4
 =item ev_tstamp ev_time ()
-Returns the current time as libev would use it.
+Returns the current time as libev would use it. Please note that the
+C<ev_now> function is usually faster and also often returns the timestamp
+you actually want to know.
 =item int ev_version_major ()
 =item int ev_version_minor ()
 This flags value could be used to implement alternative looping
 constructs, but the C<prepare> and C<check> watchers provide a better and
 more generic mechanism.
+Here are the gory details of what ev_loop does:
+   1. If there are no active watchers (reference count is zero), return.
+   2. Queue and immediately call all prepare watchers.
+   3. If we have been forked, recreate the kernel state.
+   4. Update the kernel state with all outstanding changes.
+   5. Update the "event loop time".
+   6. Calculate for how long to block.
+   7. Block the process, waiting for events.
+   8. Update the "event loop time" and do time jump handling.
+   9. Queue all outstanding timers.
+  10. Queue all outstanding periodics.
+  11. If no events are pending now, queue all idle watchers.
+  12. Queue all check watchers.
+  13. Call all queued watchers in reverse order (i.e. check watchers first).
+  14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
+      was used, return, otherwise continue with step #1.
 =item ev_unloop (loop, how)
 Can be used to make a call to C<ev_loop> return early (but only after it
 has processed all outstanding events). The C<how> argument must be either
-C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> call return, or
+C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
 C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
 =item ev_ref (loop)
 =item ev_unref (loop)
 in each iteration of the event loop (This behaviour is called
 level-triggering because you keep receiving events as long as the
 condition persists. Remember you can stop the watcher if you don't want to
 act on the event and neither want to receive future events).
-In general you can register as many read and/or write event watchers oer
+In general you can register as many read and/or write event watchers per
 fd as you want (as long as you don't confuse yourself). Setting all file
 descriptors to non-blocking mode is also usually a good idea (but not
 required if you know what you are doing).
 You have to be careful with dup'ed file descriptors, though. Some backends
 (the linux epoll backend is a notable example) cannot handle dup'ed file
 descriptors correctly if you register interest in two or more fds pointing
-to the same file/socket etc. description.
+to the same underlying file/socket etc. description (that is, they share
+the same underlying "file open").
 If you must do this, then force the use of a known-to-be-good backend
 (at the time of this writing, this includes only EVMETHOD_SELECT and
 EVMETHOD_POLL).
 Timer watchers are simple relative timers that generate an event after a
 given time, and optionally repeating in regular intervals after that.
 The timers are based on real time, that is, if you register an event that
-times out after an hour and youreset your system clock to last years
+times out after an hour and you reset your system clock to last years
 time, it will still time out after (roughly) and hour. "Roughly" because
 detecting time jumps is hard, and soem inaccuracies are unavoidable (the
 monotonic clock option helps a lot here).
 The relative timeouts are calculated relative to the C<ev_now ()>
 time. This is usually the right thing as this timestamp refers to the time
 of the event triggering whatever timeout you are modifying/starting.  If
 you suspect event processing to be delayed and you *need* to base the timeout
-ion the current time, use something like this to adjust for this:
+on the current time, use something like this to adjust for this:
    ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
 =over 4
 later, again, and again, until stopped manually.
 The timer itself will do a best-effort at avoiding drift, that is, if you
 configure a timer to trigger every 10 seconds, then it will trigger at
 exactly 10 second intervals. If, however, your program cannot keep up with
-the timer (ecause it takes longer than those 10 seconds to do stuff) the
+the timer (because it takes longer than those 10 seconds to do stuff) the
 timer will not fire more than once per event loop iteration.
 =item ev_timer_again (loop)
 This will act as if the timer timed out and restart it again if it is
 (that is, the lowest time value larger than to the second argument). It
 will usually be called just before the callback will be triggered, but
 might be called at other times, too.
 NOTE: I<< This callback must always return a time that is later than the
-passed C<now> value >>. Not even C<now> itself will do, it must be larger.
+passed C<now> value >>. Not even C<now> itself will do, it I<must> be larger.
 This can be used to create very complex timers, such as a timer that
 triggers on each midnight, local time. To do this, you would calculate the
-next midnight after C<now> and return the timestamp value for this. How you do this
+next midnight after C<now> and return the timestamp value for this. How
-is, again, up to you (but it is not trivial).
+you do this is, again, up to you (but it is not trivial, which is the main
+reason I omitted it as an example).
 =back
 =item ev_periodic_again (loop, ev_periodic *)
 =back
 =head2 C<ev_prepare> and C<ev_check> - customise your event loop
 Prepare and check watchers are usually (but not always) used in tandem:
-Prepare watchers get invoked before the process blocks and check watchers
+prepare watchers get invoked before the process blocks and check watchers
 afterwards.
 Their main purpose is to integrate other event mechanisms into libev. This
 could be used, for example, to track variable changes, implement your own
 watchers, integrate net-snmp or a coroutine library and lots more.
 to be watched by the other library, registering C<ev_io> watchers for
 them and starting an C<ev_timer> watcher for any timeouts (many libraries
 provide just this functionality). Then, in the check watcher you check for
 any events that occured (by checking the pending status of all watchers
 and stopping them) and call back into the library. The I/O and timer
-callbacks will never actually be called (but must be valid neverthelles,
+callbacks will never actually be called (but must be valid nevertheless,
 because you never know, you know?).
 As another example, the Perl Coro module uses these hooks to integrate
 coroutines into libev programs, by yielding to other active coroutines
 during each prepare and only letting the process block if no coroutines
-are ready to run (its actually more complicated, it only runs coroutines
+are ready to run (it's actually more complicated: it only runs coroutines
-with priority higher than the event loop and one lower priority once,
+with priority higher than or equal to the event loop and one coroutine
-using idle watchers to keep the event loop from blocking if lower-priority
+of lower priority, but only once, using idle watchers to keep the event
-coroutines exist, thus mapping low-priority coroutines to idle/background
+loop from blocking if lower-priority coroutines are active, thus mapping
-tasks).
+low-priority coroutines to idle/background tasks).
 =over 4
 =item ev_prepare_init (ev_prepare *, callback)
 =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)
 This function combines a simple timer and an I/O watcher, calls your
 callback on whichever event happens first and automatically stop both
 watchers. This is useful if you want to wait for a single event on an fd
-or timeout without havign to allocate/configure/start/stop/free one or
+or timeout without having to allocate/configure/start/stop/free one or
 more watchers yourself.
 If C<fd> is less than 0, then no I/O watcher will be started and events
 is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and
 C<events> set will be craeted and started.
 started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
 repeat = 0) will be started. While C<0> is a valid timeout, it is of
 dubious value.
 The callback has the type C<void (*cb)(int revents, void *arg)> and gets
-passed an events set like normal event callbacks (with a combination of
+passed an C<revents> set like normal event callbacks (a combination of
 C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
 value passed to C<ev_once>:
   static void stdin_ready (int revents, void *arg)
   {
 Feed an event as if the given signal occured (loop must be the default loop!).
 =back
+=head1 LIBEVENT EMULATION
+Libev offers a compatibility emulation layer for libevent. It cannot
+emulate the internals of libevent, so here are some usage hints:
+=over 4
+=item * Use it by including <event.h>, as usual.
+=item * The following members are fully supported: ev_base, ev_callback,
+ev_arg, ev_fd, ev_res, ev_events.
+=item * Avoid using ev_flags and the EVLIST_*-macros, while it is
+maintained by libev, it does not work exactly the same way as in libevent (consider
+it a private API).
+=item * Priorities are not currently supported. Initialising priorities
+will fail and all watchers will have the same priority, even though there
+is an ev_pri field.
+=item * Other members are not supported.
+=item * The libev emulation is I<not> ABI compatible to libevent, you need
+to use the libev header file and library.
+=back
+=head1 C++ SUPPORT
+TBD.
 =head1 AUTHOR
 Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.pod (file contents): Revision 1.18 by root, Mon Nov 12 09:01:12 2007 UTC vs. Revision 1.27 by root, Wed Nov 14 05:02:07 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.18 by root, Mon Nov 12 09:01:12 2007 UTC vs.
Revision 1.27 by root, Wed Nov 14 05:02:07 2007 UTC