[ViewVC] Diff of: cvs/libev/ev.3

Comparing libev/ev.3 (file contents):
Revision 1.89 by root, Sat Mar 24 19:38:51 2012 UTC vs.
Revision 1.99 by root, Mon Jun 10 00:14:23 2013 UTC

-.\" Automatically generated by Pod::Man 2.23 (Pod::Simple 3.14)
+.\" Automatically generated by Pod::Man 2.25 (Pod::Simple 3.20)
 .\"
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 .\" ========================================================================
 .de Sp \" Vertical space (when we can't use .PP)
 .if t .sp .5v
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 .rm #[ #] #H #V #F C
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 .IX Title "LIBEV 3"
-.TH LIBEV 3 "2012-03-23" "libev-4.11" "libev - high performance full featured event loop"
+.TH LIBEV 3 "2013-06-07" "libev-4.15" "libev - high performance full featured event loop"
 .\" For nroff, turn off justification.  Always turn off hyphenation; it makes
 .\" way too many mistakes in technical documents.
 .if n .ad l
 .nh
 .SH "NAME"
 current system. To find which embeddable backends might be supported on
 the current system, you would need to look at \f(CW\*(C`ev_embeddable_backends ()
 & ev_supported_backends ()\*(C'\fR, likewise for recommended ones.
 .Sp
 See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
-.IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4
+.IP "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())" 4
-.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))"
+.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())"
 Sets the allocation function to use (the prototype is similar \- the
 semantics are identical to the \f(CW\*(C`realloc\*(C'\fR C89/SuS/POSIX function). It is
 used to allocate and free memory (no surprises here). If it returns zero
 when memory needs to be allocated (\f(CW\*(C`size != 0\*(C'\fR), the library might abort
 or take some potentially destructive action.
 \&   }
 \&
 \&   ...
 \&   ev_set_allocator (persistent_realloc);
 .Ve
-.IP "ev_set_syserr_cb (void (*cb)(const char *msg))" 4
+.IP "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())" 4
-.IX Item "ev_set_syserr_cb (void (*cb)(const char *msg))"
+.IX Item "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())"
 Set the callback function to call on a retryable system call error (such
 as failed select, poll, epoll_wait). The message is a printable string
 indicating the system call or subsystem causing the problem. If this
 callback is set, then libev will expect it to remedy the situation, no
 matter what, when it returns. That is, libev will generally retry the
 .IX Item "EVFLAG_NOENV"
 If this flag bit is or'ed into the flag value (or the program runs setuid
 or setgid) then libev will \fInot\fR look at the environment variable
 \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will
 override the flags completely if it is found in the environment. This is
-useful to try out specific backends to test their performance, or to work
+useful to try out specific backends to test their performance, to work
-around bugs.
+around bugs, or to make libev threadsafe (accessing environment variables
+cannot be done in a threadsafe way, but usually it works if no other
+thread modifies them).
 .ie n .IP """EVFLAG_FORKCHECK""" 4
 .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4
 .IX Item "EVFLAG_FORKCHECK"
 Instead of calling \f(CW\*(C`ev_loop_fork\*(C'\fR manually after a fork, you can also
 make libev check for a fork in each iteration by enabling this flag.
 .Sp
 It scales in the same way as the epoll backend, but the interface to the
 kernel is more efficient (which says nothing about its actual speed, of
 course). While stopping, setting and starting an I/O watcher does never
 cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to
-two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (but
+two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you
-sane, unlike epoll) and it drops fds silently in similarly hard-to-detect
+might have to leak fd's on fork, but it's more sane than epoll) and it
-cases
+drops fds silently in similarly hard-to-detect cases.
 .Sp
 This backend usually performs well under most conditions.
 .Sp
 While nominally embeddable in other event loops, this doesn't work
 everywhere, so you might need to test for this. And since it is broken
 given loop other than \f(CW\*(C`ev_resume\*(C'\fR, and you \fBmust not\fR call \f(CW\*(C`ev_resume\*(C'\fR
 without a previous call to \f(CW\*(C`ev_suspend\*(C'\fR.
 .Sp
 Calling \f(CW\*(C`ev_suspend\*(C'\fR/\f(CW\*(C`ev_resume\*(C'\fR has the side effect of updating the
 event loop time (see \f(CW\*(C`ev_now_update\*(C'\fR).
-.IP "ev_run (loop, int flags)" 4
+.IP "bool ev_run (loop, int flags)" 4
-.IX Item "ev_run (loop, int flags)"
+.IX Item "bool ev_run (loop, int flags)"
 Finally, this is it, the event handler. This function usually is called
 after you have initialised all your watchers and you want to start
 handling events. It will ask the operating system for any new events, call
-the watcher callbacks, an then repeat the whole process indefinitely: This
+the watcher callbacks, and then repeat the whole process indefinitely: This
 is why event loops are called \fIloops\fR.
 .Sp
 If the flags argument is specified as \f(CW0\fR, it will keep handling events
 until either no event watchers are active anymore or \f(CW\*(C`ev_break\*(C'\fR was
 called.
+.Sp
+The return value is false if there are no more active watchers (which
+usually means \*(L"all jobs done\*(R" or \*(L"deadlock\*(R"), and true in all other cases
+(which usually means " you should call \f(CW\*(C`ev_run\*(C'\fR again").
 .Sp
 Please note that an explicit \f(CW\*(C`ev_break\*(C'\fR is usually better than
 relying on all watchers to be stopped when deciding when a program has
 finished (especially in interactive programs), but having a program
 that automatically loops as long as it has to and no longer by virtue
 of relying on its watchers stopping correctly, that is truly a thing of
 beauty.
 .Sp
-This function is also \fImostly\fR exception-safe \- you can break out of
+This function is \fImostly\fR exception-safe \- you can break out of a
-a \f(CW\*(C`ev_run\*(C'\fR call by calling \f(CW\*(C`longjmp\*(C'\fR in a callback, throwing a \*(C+
+\&\f(CW\*(C`ev_run\*(C'\fR call by calling \f(CW\*(C`longjmp\*(C'\fR in a callback, throwing a \*(C+
 exception and so on. This does not decrement the \f(CW\*(C`ev_depth\*(C'\fR value, nor
 will it clear any outstanding \f(CW\*(C`EVBREAK_ONE\*(C'\fR breaks.
 .Sp
 A flags value of \f(CW\*(C`EVRUN_NOWAIT\*(C'\fR will look for new events, will handle
 those events and any already outstanding ones, but will not wait and
 this callback instead. This is useful, for example, when you want to
 invoke the actual watchers inside another context (another thread etc.).
 .Sp
 If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new
 callback.
-.IP "ev_set_loop_release_cb (loop, void (*release)(\s-1EV_P\s0), void (*acquire)(\s-1EV_P\s0))" 4
+.IP "ev_set_loop_release_cb (loop, void (*release)(\s-1EV_P\s0) throw (), void (*acquire)(\s-1EV_P\s0) throw ())" 4
-.IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P), void (*acquire)(EV_P))"
+.IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P) throw (), void (*acquire)(EV_P) throw ())"
 Sometimes you want to share the same loop between multiple threads. This
 can be done relatively simply by putting mutex_lock/unlock calls around
 each call to a libev function.
 .Sp
 However, \f(CW\*(C`ev_run\*(C'\fR can run an indefinite time, so it is not feasible
 .PD 0
 .ie n .IP """EV_CHECK""" 4
 .el .IP "\f(CWEV_CHECK\fR" 4
 .IX Item "EV_CHECK"
 .PD
-All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts
+All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts to
-to gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are invoked just after
+gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are queued (not invoked)
-\&\f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it invokes any callbacks for any
+just after \f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it queues any callbacks
+for any received events. That means \f(CW\*(C`ev_prepare\*(C'\fR watchers are the last
+watchers invoked before the event loop sleeps or polls for new events, and
+\&\f(CW\*(C`ev_check\*(C'\fR watchers will be invoked before any other watchers of the same
+or lower priority within an event loop iteration.
+.Sp
-received events. Callbacks of both watcher types can start and stop as
+Callbacks of both watcher types can start and stop as many watchers as
-many watchers as they want, and all of them will be taken into account
+they want, and all of them will be taken into account (for example, a
-(for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep
+\&\f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep \f(CW\*(C`ev_run\*(C'\fR from
-\&\f(CW\*(C`ev_run\*(C'\fR from blocking).
+blocking).
 .ie n .IP """EV_EMBED""" 4
 .el .IP "\f(CWEV_EMBED\fR" 4
 .IX Item "EV_EMBED"
 The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention.
 .ie n .IP """EV_FORK""" 4
 make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR
 it).
 .IP "callback ev_cb (ev_TYPE *watcher)" 4
 .IX Item "callback ev_cb (ev_TYPE *watcher)"
 Returns the callback currently set on the watcher.
-.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
+.IP "ev_set_cb (ev_TYPE *watcher, callback)" 4
-.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
+.IX Item "ev_set_cb (ev_TYPE *watcher, callback)"
 Change the callback. You can change the callback at virtually any time
 (modulo threads).
 .IP "ev_set_priority (ev_TYPE *watcher, int priority)" 4
 .IX Item "ev_set_priority (ev_TYPE *watcher, int priority)"
 .PD 0
 .IX Subsection "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 \*(L"the right thing\*(R".
-.IP "initialiased" 4
+.IP "initialised" 4
-.IX Item "initialiased"
+.IX Item "initialised"
 Before a watcher can be registered with the event loop it has to be
 initialised. This can be done with a call to \f(CW\*(C`ev_TYPE_init\*(C'\fR, or calls to
 \&\f(CW\*(C`ev_init\*(C'\fR followed by the watcher-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR function.
 .Sp
 In this state it is simply some block of memory that is suitable for
 \&   callback (EV_P_ ev_timer *w, int revents)
 \&   {
 \&     // calculate when the timeout would happen
 \&     ev_tstamp after = last_activity \- ev_now (EV_A) + timeout;
 \&
-\&     // if negative, it means we the timeout already occured
+\&     // if negative, it means we the timeout already occurred
 \&     if (after < 0.)
 \&       {
 \&         // timeout occurred, take action
 \&       }
 \&     else
 .Sp
 Otherwise, we now the earliest time at which the timeout would trigger,
 and simply start the timer with this timeout value.
 .Sp
 In other words, each time the callback is invoked it will check whether
-the timeout cocured. If not, it will simply reschedule itself to check
+the timeout occurred. If not, it will simply reschedule itself to check
 again at the earliest time it could time out. Rinse. Repeat.
 .Sp
 This scheme causes more callback invocations (about one every 60 seconds
 minus half the average time between activity), but virtually no calls to
 libev to change the timeout.
 \&     last_activity = ev_now (EV_A);
 .Ve
 .Sp
 When your timeout value changes, then the timeout can be changed by simply
 providing a new value, stopping the timer and calling the callback, which
-will agaion do the right thing (for example, time out immediately :).
+will again do the right thing (for example, time out immediately :).
 .Sp
 .Vb 3
 \&   timeout = new_value;
 \&   ev_timer_stop (EV_A_ &timer);
 \&   callback (EV_A_ &timer, 0);
 .ie n .SS """ev_stat"" \- did the file attributes just change?"
 .el .SS "\f(CWev_stat\fP \- did the file attributes just change?"
 .IX Subsection "ev_stat - did the file attributes just change?"
 This watches a file system path for attribute changes. That is, it calls
 \&\f(CW\*(C`stat\*(C'\fR on that path in regular intervals (or when the \s-1OS\s0 says it changed)
-and sees if it changed compared to the last time, invoking the callback if
+and sees if it changed compared to the last time, invoking the callback
-it did.
+if it did. Starting the watcher \f(CW\*(C`stat\*(C'\fR's the file, so only changes that
+happen after the watcher has been started will be reported.
 .PP
 The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does
 not exist\*(R" is a status change like any other. The condition \*(L"path does not
 exist\*(R" (or more correctly \*(L"path cannot be stat'ed\*(R") is signified by the
 \&\f(CW\*(C`st_nlink\*(C'\fR field being zero (which is otherwise always forced to be at
 Apart from keeping your process non-blocking (which is a useful
 effect on its own sometimes), idle watchers are a good place to do
 \&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the
 event loop has handled all outstanding events.
 .PP
+\fIAbusing an \f(CI\*(C`ev_idle\*(C'\fI watcher for its side-effect\fR
+.IX Subsection "Abusing an ev_idle watcher for its side-effect"
+.PP
+As long as there is at least one active idle watcher, libev will never
+sleep unnecessarily. Or in other words, it will loop as fast as possible.
+For this to work, the idle watcher doesn't need to be invoked at all \- the
+lowest priority will do.
+.PP
+This mode of operation can be useful together with an \f(CW\*(C`ev_check\*(C'\fR watcher,
+to do something on each event loop iteration \- for example to balance load
+between different connections.
+.PP
+See \*(L"Abusing an ev_check watcher for its side-effect\*(R" for a longer
+example.
+.PP
 \fIWatcher-Specific Functions and Data Members\fR
 .IX Subsection "Watcher-Specific Functions and Data Members"
 .IP "ev_idle_init (ev_idle *, callback)" 4
 .IX Item "ev_idle_init (ev_idle *, callback)"
 Initialises and configures the idle watcher \- it has no parameters of any
 .IX Subsection "Examples"
 .PP
 Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the
 callback, free it. Also, use no error checking, as usual.
 .PP
-.Vb 7
+.Vb 5
 \&   static void
 \&   idle_cb (struct ev_loop *loop, ev_idle *w, int revents)
 \&   {
+\&     // stop the watcher
+\&     ev_idle_stop (loop, w);
+\&
+\&     // now we can free it
 \&     free (w);
+\&
 \&     // now do something you wanted to do when the program has
 \&     // no longer anything immediate to do.
 \&   }
 \&
 \&   ev_idle *idle_watcher = malloc (sizeof (ev_idle));
 \&   ev_idle_start (loop, idle_watcher);
 .Ve
 .ie n .SS """ev_prepare"" and ""ev_check"" \- customise your event loop!"
 .el .SS "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
 .IX Subsection "ev_prepare and ev_check - customise your event loop!"
-Prepare and check watchers are usually (but not always) used in pairs:
+Prepare and check watchers are often (but not always) used in pairs:
 prepare watchers get invoked before the process blocks and check watchers
 afterwards.
 .PP
 You \fImust not\fR call \f(CW\*(C`ev_run\*(C'\fR or similar functions that enter
 the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR
 with priority higher than or equal to the event loop and one coroutine
 of lower priority, but only once, using idle watchers to keep the event
 loop from blocking if lower-priority coroutines are active, thus mapping
 low-priority coroutines to idle/background tasks).
 .PP
-It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR)
+When used for this purpose, it is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers
-priority, to ensure that they are being run before any other watchers
+highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) priority, to ensure that they are being run before
-after the poll (this doesn't matter for \f(CW\*(C`ev_prepare\*(C'\fR watchers).
+any other watchers after the poll (this doesn't matter for \f(CW\*(C`ev_prepare\*(C'\fR
+watchers).
 .PP
 Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, too) should not
 activate (\*(L"feed\*(R") events into libev. While libev fully supports this, they
 might get executed before other \f(CW\*(C`ev_check\*(C'\fR watchers did their job. As
 \&\f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other (non-libev) event
 loops those other event loops might be in an unusable state until their
 \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with
 others).
+.PP
+\fIAbusing an \f(CI\*(C`ev_check\*(C'\fI watcher for its side-effect\fR
+.IX Subsection "Abusing an ev_check watcher for its side-effect"
+.PP
+\&\f(CW\*(C`ev_check\*(C'\fR (and less often also \f(CW\*(C`ev_prepare\*(C'\fR) watchers can also be
+useful because they are called once per event loop iteration. For
+example, if you want to handle a large number of connections fairly, you
+normally only do a bit of work for each active connection, and if there
+is more work to do, you wait for the next event loop iteration, so other
+connections have a chance of making progress.
+.PP
+Using an \f(CW\*(C`ev_check\*(C'\fR watcher is almost enough: it will be called on the
+next event loop iteration. However, that isn't as soon as possible \-
+without external events, your \f(CW\*(C`ev_check\*(C'\fR watcher will not be invoked.
+.PP
+This is where \f(CW\*(C`ev_idle\*(C'\fR watchers come in handy \- all you need is a
+single global idle watcher that is active as long as you have one active
+\&\f(CW\*(C`ev_check\*(C'\fR watcher. The \f(CW\*(C`ev_idle\*(C'\fR watcher makes sure the event loop
+will not sleep, and the \f(CW\*(C`ev_check\*(C'\fR watcher makes sure a callback gets
+invoked. Neither watcher alone can do that.
 .PP
 \fIWatcher-Specific Functions and Data Members\fR
 .IX Subsection "Watcher-Specific Functions and Data Members"
 .IP "ev_prepare_init (ev_prepare *, callback)" 4
 .IX Item "ev_prepare_init (ev_prepare *, callback)"
 \fIWatcher-Specific Functions and Data Members\fR
 .IX Subsection "Watcher-Specific Functions and Data Members"
 .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4
 .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)"
 .PD 0
-.IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4
+.IP "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)" 4
-.IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)"
+.IX Item "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)"
 .PD
 Configures the watcher to embed the given loop, which must be
 embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be
 invoked automatically, otherwise it is the responsibility of the callback
 to invoke it (it will continue to be called until the sweep has been done,
 .ie n .SS """ev_fork"" \- the audacity to resume the event loop after a fork"
 .el .SS "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
 .IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
 Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because
 whoever is a good citizen cared to tell libev about it by calling
-\&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the
+\&\f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the event loop blocks next
-event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called,
+and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, and only in the child
-and only in the child after the fork. If whoever good citizen calling
+after the fork. If whoever good citizen calling \f(CW\*(C`ev_default_fork\*(C'\fR cheats
-\&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork
+and calls it in the wrong process, the fork handlers will be invoked, too,
-handlers will be invoked, too, of course.
+of course.
 .PP
 \fIThe special problem of life after fork \- how is it possible?\fR
 .IX Subsection "The special problem of life after fork - how is it possible?"
 .PP
 Most uses of \f(CW\*(C`fork()\*(C'\fR consist of forking, then some simple calls to set
 it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal safe.
 .PP
 This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals,
 too, are asynchronous in nature, and signals, too, will be compressed
 (i.e. the number of callback invocations may be less than the number of
-\&\f(CW\*(C`ev_async_sent\*(C'\fR calls). In fact, you could use signal watchers as a kind
+\&\f(CW\*(C`ev_async_send\*(C'\fR calls). In fact, you could use signal watchers as a kind
 of \*(L"global async watchers\*(R" by using a watcher on an otherwise unused
 signal, and \f(CW\*(C`ev_feed_signal\*(C'\fR to signal this watcher from another thread,
 even without knowing which loop owns the signal.
 .PP
 \fIQueueing\fR
 already been invoked.
 .PP
 A common way around all these issues is to make sure that
 \&\f(CW\*(C`start_new_request\*(C'\fR \fIalways\fR returns before the callback is invoked. If
 \&\f(CW\*(C`start_new_request\*(C'\fR immediately knows the result, it can artificially
-delay invoking the callback by e.g. using a \f(CW\*(C`prepare\*(C'\fR or \f(CW\*(C`idle\*(C'\fR watcher
+delay invoking the callback by using a \f(CW\*(C`prepare\*(C'\fR or \f(CW\*(C`idle\*(C'\fR watcher for
-for example, or more sneakily, by reusing an existing (stopped) watcher
+example, or more sneakily, by reusing an existing (stopped) watcher and
-and pushing it into the pending queue:
+pushing it into the pending queue:
 .PP
 .Vb 2
 \&   ev_set_cb (watcher, callback);
 \&   ev_feed_event (EV_A_ watcher, 0);
 .Ve
 .PP
 This brings the problem of exiting \- a callback might want to finish the
 main \f(CW\*(C`ev_run\*(C'\fR call, but not the nested one (e.g. user clicked \*(L"Quit\*(R", but
 a modal \*(L"Are you sure?\*(R" dialog is still waiting), or just the nested one
 and not the main one (e.g. user clocked \*(L"Ok\*(R" in a modal dialog), or some
-other combination: In these cases, \f(CW\*(C`ev_break\*(C'\fR will not work alone.
+other combination: In these cases, a simple \f(CW\*(C`ev_break\*(C'\fR will not work.
 .PP
 The solution is to maintain \*(L"break this loop\*(R" variable for each \f(CW\*(C`ev_run\*(C'\fR
 invocation, and use a loop around \f(CW\*(C`ev_run\*(C'\fR until the condition is
 triggered, using \f(CW\*(C`EVRUN_ONCE\*(C'\fR:
 .PP
 .PP
 .Vb 6
 \&   void
 \&   wait_for_event (ev_watcher *w)
 \&   {
-\&     ev_cb_set (w) = current_coro;
+\&     ev_set_cb (w, current_coro);
 \&     switch_to (libev_coro);
 \&   }
 .Ve
 .PP
 That basically suspends the coroutine inside \f(CW\*(C`wait_for_event\*(C'\fR and
 You can do similar tricks if you have, say, threads with an event queue \-
 instead of storing a coroutine, you store the queue object and instead of
 switching to a coroutine, you push the watcher onto the queue and notify
 any waiters.
 .PP
-To embed libev, see \s-1EMBEDDING\s0, but in short, it's easiest to create two
+To embed libev, see \*(L"\s-1EMBEDDING\s0\*(R", but in short, it's easiest to create two
 files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files:
 .PP
 .Vb 4
 \&   // my_ev.h
 \&   #define EV_CB_DECLARE(type)   struct my_coro *cb;
 .IP "\(bu" 4
 The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need
 to use the libev header file and library.
 .SH "\*(C+ SUPPORT"
 .IX Header " SUPPORT"
+.SS "C \s-1API\s0"
+.IX Subsection "C API"
+The normal C \s-1API\s0 should work fine when used from \*(C+: both ev.h and the
+libev sources can be compiled as \*(C+. Therefore, code that uses the C \s-1API\s0
+will work fine.
+.PP
+Proper exception specifications might have to be added to callbacks passed
+to libev: exceptions may be thrown only from watcher callbacks, all
+other callbacks (allocator, syserr, loop acquire/release and periodic
+reschedule callbacks) must not throw exceptions, and might need a \f(CW\*(C`throw
+()\*(C'\fR specification. If you have code that needs to be compiled as both C
+and \*(C+ you can use the \f(CW\*(C`EV_THROW\*(C'\fR macro for this:
+.PP
+.Vb 6
+\&   static void
+\&   fatal_error (const char *msg) EV_THROW
+\&   {
+\&     perror (msg);
+\&     abort ();
+\&   }
+\&
+\&   ...
+\&   ev_set_syserr_cb (fatal_error);
+.Ve
+.PP
+The only \s-1API\s0 functions that can currently throw exceptions are \f(CW\*(C`ev_run\*(C'\fR,
+\&\f(CW\*(C`ev_invoke\*(C'\fR, \f(CW\*(C`ev_invoke_pending\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR (the latter
+because it runs cleanup watchers).
+.PP
+Throwing exceptions in watcher callbacks is only supported if libev itself
+is compiled with a \*(C+ compiler or your C and \*(C+ environments allow
+throwing exceptions through C libraries (most do).
+.SS "\*(C+ \s-1API\s0"
+.IX Subsection " API"
 Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow
 you to use some convenience methods to start/stop watchers and also change
 the callback model to a model using method callbacks on objects.
 .PP
 To use it,
 .IX Item "w->set (loop)"
 Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only
 do this when the watcher is inactive (and not pending either).
 .IP "w\->set ([arguments])" 4
 .IX Item "w->set ([arguments])"
-Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same arguments. Either this
+Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR (except for \f(CW\*(C`ev::embed\*(C'\fR watchers>),
-method or a suitable start method must be called at least once. Unlike the
+with the same arguments. Either this method or a suitable start method
-C counterpart, an active watcher gets automatically stopped and restarted
+must be called at least once. Unlike the C counterpart, an active watcher
-when reconfiguring it with this method.
+gets automatically stopped and restarted when reconfiguring it with this
+method.
+.Sp
+For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid
+clashing with the \f(CW\*(C`set (loop)\*(C'\fR method.
 .IP "w\->start ()" 4
 .IX Item "w->start ()"
 Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the
 constructor already stores the event loop.
 .IP "w\->start ([arguments])" 4
 .IP "Lua" 4
 .IX Item "Lua"
 Brian Maher has written a partial interface to libev for lua (at the
 time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at
 http://github.com/brimworks/lua\-ev <http://github.com/brimworks/lua-ev>.
+.IP "Javascript" 4
+.IX Item "Javascript"
+Node.js (<http://nodejs.org>) uses libev as the underlying event library.
+.IP "Others" 4
+.IX Item "Others"
+There are others, and I stopped counting.
 .SH "MACRO MAGIC"
 .IX Header "MACRO MAGIC"
 Libev can be compiled with a variety of options, the most fundamental
 of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most)
 functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument.
 .IX Item "EV_WIN32_CLOSE_FD(fd)"
 If programs implement their own fd to handle mapping on win32, then this
 macro can be used to override the \f(CW\*(C`close\*(C'\fR function, useful to unregister
 file descriptors again. Note that the replacement function has to close
 the underlying \s-1OS\s0 handle.
+.IP "\s-1EV_USE_WSASOCKET\s0" 4
+.IX Item "EV_USE_WSASOCKET"
+If defined to be \f(CW1\fR, libev will use \f(CW\*(C`WSASocket\*(C'\fR to create its internal
+communication socket, which works better in some environments. Otherwise,
+the normal \f(CW\*(C`socket\*(C'\fR function will be used, which works better in other
+environments.
 .IP "\s-1EV_USE_POLL\s0" 4
 .IX Item "EV_USE_POLL"
 If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2)
 backend. Otherwise it will be enabled on non\-win32 platforms. It
 takes precedence over select.
 between threads, that is, threads can be used, but threads never run on
 different cpus (or different cpu cores). This reduces dependencies
 and makes libev faster.
 .IP "\s-1EV_NO_THREADS\s0" 4
 .IX Item "EV_NO_THREADS"
-If defined to be \f(CW1\fR, libev will assume that it will never be called
+If defined to be \f(CW1\fR, libev will assume that it will never be called from
-from different threads, which is a stronger assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR,
+different threads (that includes signal handlers), which is a stronger
-above. This reduces dependencies and makes libev faster.
+assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR, above. This reduces dependencies and makes
+libev faster.
 .IP "\s-1EV_ATOMIC_T\s0" 4
 .IX Item "EV_ATOMIC_T"
 Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose
-access is atomic and serialised with respect to other threads or signal
+access is atomic with respect to other threads or signal contexts. No
-contexts. No such type is easily found in the C language, so you can
+such type is easily found in the C language, so you can provide your own
-provide your own type that you know is safe for your purposes. It is used
+type that you know is safe for your purposes. It is used both for signal
-both for signal handler \*(L"locking\*(R" as well as for signal and thread safety
+handler \*(L"locking\*(R" as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR
-in \f(CW\*(C`ev_async\*(C'\fR watchers.
+watchers.
 .Sp
 In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR
-(from \fIsignal.h\fR), which is usually good enough on most platforms,
+(from \fIsignal.h\fR), which is usually good enough on most platforms.
-although strictly speaking using a type that also implies a memory fence
-is required.
 .IP "\s-1EV_H\s0 (h)" 4
 .IX Item "EV_H (h)"
 The name of the \fIev.h\fR header file used to include it. The default if
 undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be
 used to virtually rename the \fIev.h\fR header file in case of conflicts.
 \&   #define EV_CHILD_ENABLE 1
 \&   #define EV_ASYNC_ENABLE 1
 .Ve
 .Sp
 The actual value is a bitset, it can be a combination of the following
-values:
+values (by default, all of these are enabled):
 .RS 4
 .ie n .IP "1 \- faster/larger code" 4
 .el .IP "\f(CW1\fR \- faster/larger code" 4
 .IX Item "1 - faster/larger code"
 Use larger code to speed up some operations.
 code size by roughly 30% on amd64).
 .Sp
 When optimising for size, use of compiler flags such as \f(CW\*(C`\-Os\*(C'\fR with
 gcc is recommended, as well as \f(CW\*(C`\-DNDEBUG\*(C'\fR, as libev contains a number of
 assertions.
+.Sp
+The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler
+(e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR).
 .ie n .IP "2 \- faster/larger data structures" 4
 .el .IP "\f(CW2\fR \- faster/larger data structures" 4
 .IX Item "2 - faster/larger data structures"
 Replaces the small 2\-heap for timer management by a faster 4\-heap, larger
 hash table sizes and so on. This will usually further increase code size
 and can additionally have an effect on the size of data structures at
 runtime.
+.Sp
+The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler
+(e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR).
 .ie n .IP "4 \- full \s-1API\s0 configuration" 4
 .el .IP "\f(CW4\fR \- full \s-1API\s0 configuration" 4
 .IX Item "4 - full API configuration"
 This enables priorities (sets \f(CW\*(C`EV_MAXPRI\*(C'\fR=2 and \f(CW\*(C`EV_MINPRI\*(C'\fR=\-2), and
 enables multiplicity (\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR=1).
 thread\*(R" or will block signals process-wide, both behaviours would
 be compatible with libev. Interaction between \f(CW\*(C`sigprocmask\*(C'\fR and
 \&\f(CW\*(C`pthread_sigmask\*(C'\fR could complicate things, however.
 .Sp
 The most portable way to handle signals is to block signals in all threads
-except the initial one, and run the default loop in the initial thread as
+except the initial one, and run the signal handling loop in the initial
-well.
+thread as well.
 .ie n .IP """long"" must be large enough for common memory allocation sizes" 4
 .el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4
 .IX Item "long must be large enough for common memory allocation sizes"
 To improve portability and simplify its \s-1API\s0, libev uses \f(CW\*(C`long\*(C'\fR internally
 instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX
 new \s-1API\s0 early than late.
 .ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4
 .el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4
 .IX Item "EV_COMPAT3 backwards compatibility mechanism"
 The backward compatibility mechanism can be controlled by
-\&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1MACROS\s0\*(R" in \s-1PREPROCESSOR\s0 \s-1SYMBOLS\s0 in the \s-1EMBEDDING\s0
+\&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0\*(R" in the \*(L"\s-1EMBEDDING\s0\*(R"
 section.
 .ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4
 .el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4
 .IX Item "ev_default_destroy and ev_default_fork have been removed"
 These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts:

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Comparing libev/ev.3 (file contents): Revision 1.89 by root, Sat Mar 24 19:38:51 2012 UTC vs. Revision 1.99 by root, Mon Jun 10 00:14:23 2013 UTC

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Comparing libev/ev.3 (file contents):
Revision 1.89 by root, Sat Mar 24 19:38:51 2012 UTC vs.
Revision 1.99 by root, Mon Jun 10 00:14:23 2013 UTC