--- libev/ev.pod	2008/10/24 08:26:04	1.201
+++ libev/ev.pod	2009/04/15 19:35:53	1.231
@@ -11,6 +11,8 @@
    // a single header file is required
    #include <ev.h>
 
+   #include <stdio.h> // for puts
+
    // every watcher type has its own typedef'd struct
    // with the name ev_TYPE
    ev_io stdin_watcher;
@@ -43,7 +45,7 @@
    main (void)
    {
      // use the default event loop unless you have special needs
-     ev_loop *loop = ev_default_loop (0);
+     struct ev_loop *loop = ev_default_loop (0);
 
      // initialise an io watcher, then start it
      // this one will watch for stdin to become readable
@@ -300,7 +302,7 @@
 
 Note that this function is I<not> thread-safe, so if you want to use it
 from multiple threads, you have to lock (note also that this is unlikely,
-as loops cannot bes hared easily between threads anyway).
+as loops cannot be shared easily between threads anyway).
 
 The default loop is the only loop that can handle C<ev_signal> and
 C<ev_child> watchers, and to do this, it always registers a handler
@@ -386,26 +388,43 @@
 For few fds, this backend is a bit little slower than poll and select,
 but it scales phenomenally better. While poll and select usually scale
 like O(total_fds) where n is the total number of fds (or the highest fd),
-epoll scales either O(1) or O(active_fds). The epoll design has a number
-of shortcomings, such as silently dropping events in some hard-to-detect
-cases and requiring a system call per fd change, no fork support and bad
-support for dup.
+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
+so 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
+of course I<doesn't>, and epoll just loves to report events for totally
+I<different> file descriptors (even already closed ones, so one cannot
+even remove them from the set) than registered in the set (especially
+on SMP systems). Libev tries to counter these spurious notifications by
+employing an additional generation counter and comparing that against the
+events to filter out spurious ones, recreating the set when required.
 
 While stopping, setting and starting an I/O watcher in the same iteration
-will result in some caching, there is still a system call per such incident
-(because the fd could point to a different file description now), so its
-best to avoid that. Also, C<dup ()>'ed file descriptors might not work
-very well if you register events for both fds.
-
-Please note that epoll sometimes generates spurious notifications, so you
-need to use non-blocking I/O or other means to avoid blocking when no data
-(or space) is available.
+will result in some caching, there is still a system call per such
+incident (because the same I<file descriptor> could point to a different
+I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
+file descriptors might not work very well if you register events for both
+file descriptors.
 
 Best performance from this backend is achieved by not unregistering all
 watchers for a file descriptor until it has been closed, if possible,
 i.e. keep at least one watcher active per fd at all times. Stopping and
 starting a watcher (without re-setting it) also usually doesn't cause
-extra overhead.
+extra overhead. A fork can both result in spurious notifications as well
+as in libev having to destroy and recreate the epoll object, which can
+take considerable time and thus should be avoided.
+
+All this means that, in practice, C<EVBACKEND_SELECT> can be as fast or
+faster than epoll for maybe up to a hundred file descriptors, depending on
+the usage. So sad.
 
 While nominally embeddable in other event loops, this feature is broken in
 all kernel versions tested so far.
@@ -415,12 +434,15 @@
 
 =item C<EVBACKEND_KQUEUE>  (value 8, most BSD clones)
 
-Kqueue deserves special mention, as at the time of this writing, it was
-broken on all BSDs except NetBSD (usually it doesn't work reliably with
-anything but sockets and pipes, except on Darwin, where of course it's
-completely useless). For this reason it's not being "auto-detected" unless
-you explicitly specify it in the flags (i.e. using C<EVBACKEND_KQUEUE>) or
-libev was compiled on a known-to-be-good (-enough) system like NetBSD.
+Kqueue deserves special mention, as at the time of this writing, it
+was broken on all BSDs except NetBSD (usually it doesn't work reliably
+with anything but sockets and pipes, except on Darwin, where of course
+it's completely useless). Unlike epoll, however, whose brokenness
+is by design, these kqueue bugs can (and eventually will) be fixed
+without API changes to existing programs. For this reason it's not being
+"auto-detected" unless you explicitly specify it in the flags (i.e. using
+C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)
+system like NetBSD.
 
 You still can embed kqueue into a normal poll or select backend and use it
 only for sockets (after having made sure that sockets work with kqueue on
@@ -430,8 +452,9 @@
 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 C<EVBACKEND_EPOLL>, it still adds up to
-two event changes per incident. Support for C<fork ()> is very bad and it
-drops fds silently in similarly hard-to-detect cases.
+two event changes per incident. Support for C<fork ()> is very bad (but
+sane, unlike epoll) and it drops fds silently in similarly hard-to-detect
+cases
 
 This backend usually performs well under most conditions.
 
@@ -439,8 +462,8 @@
 everywhere, so you might need to test for this. And since it is broken
 almost everywhere, you should only use it when you have a lot of sockets
 (for which it usually works), by embedding it into another event loop
-(e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>) and, did I mention it,
-using it only for sockets.
+(e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> (but C<poll> is of course
+also broken on OS X)) and, did I mention it, using it only for sockets.
 
 This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with
 C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with
@@ -470,7 +493,7 @@
 On the positive side, with the exception of the spurious readiness
 notifications, this backend actually performed fully to specification
 in all tests and is fully embeddable, which is a rare feat among the
-OS-specific backends.
+OS-specific backends (I vastly prefer correctness over speed hacks).
 
 This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
 C<EVBACKEND_POLL>.
@@ -533,9 +556,9 @@
 the easiest thing, you can just ignore the watchers and/or C<free ()> them
 for example).
 
-Note that certain global state, such as signal state, will not be freed by
-this function, and related watchers (such as signal and child watchers)
-would need to be stopped manually.
+Note that certain global state, such as signal state (and installed signal
+handlers), will not be freed by this function, and related watchers (such
+as signal and child watchers) would need to be stopped manually.
 
 In general it is not advisable to call this function except in the
 rare occasion where you really need to free e.g. the signal handling
@@ -613,6 +636,32 @@
 
 See also "The special problem of time updates" in the C<ev_timer> section.
 
+=item ev_suspend (loop)
+
+=item ev_resume (loop)
+
+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 C<^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 C<ev_suspend>
+in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
+C<ev_resume> directly afterwards to resume timer processing.
+
+Effectively, all C<ev_timer> watchers will be delayed by the time spend
+between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
+will be rescheduled (that is, they will lose any events that would have
+occured while suspended).
+
+After calling C<ev_suspend> you B<must not> call I<any> function on the
+given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
+without a previous call to C<ev_suspend>.
+
+Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
+event loop time (see C<ev_now_update>).
+
 =item ev_loop (loop, int flags)
 
 Finally, this is it, the event handler. This function usually is called
@@ -637,7 +686,7 @@
 A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if
 necessary) and will handle those and any already outstanding ones. It
 will block your process until at least one new event arrives (which could
-be an event internal to libev itself, so there is no guarentee that a
+be an event internal to libev itself, so there is no guarantee that a
 user-registered callback will be called), and will return after one
 iteration of the loop.
 
@@ -705,13 +754,15 @@
 from returning, call ev_unref() after starting, and ev_ref() before
 stopping it.
 
-As an example, libev itself uses this for its internal signal pipe: It is
-not visible to the libev user and should not keep C<ev_loop> from exiting
-if no event watchers registered by it are active. It is also an excellent
-way to do this for generic recurring timers or from within third-party
-libraries. Just remember to I<unref after start> and I<ref before stop>
-(but only if the watcher wasn't active before, or was active before,
-respectively).
+As an example, libev itself uses this for its internal signal pipe: It
+is not visible to the libev user and should not keep C<ev_loop> from
+exiting if no event watchers registered by it are active. It is also an
+excellent way to do this for generic recurring timers or from within
+third-party libraries. Just remember to I<unref after start> and I<ref
+before stop> (but only if the watcher wasn't active before, or was active
+before, respectively. Note also that libev might stop watchers itself
+(e.g. non-repeating timers) in which case you have to C<ev_ref>
+in the callback).
 
 Example: Create a signal watcher, but keep it from keeping C<ev_loop>
 running when nothing else is active.
@@ -905,6 +956,11 @@
 
 The given async watcher has been asynchronously notified (see C<ev_async>).
 
+=item C<EV_CUSTOM>
+
+Not ever sent (or otherwise used) by libev itself, but can be freely used
+by libev users to signal watchers (e.g. via C<ev_feed_event>).
+
 =item C<EV_ERROR>
 
 An unspecified error has occurred, the watcher has been stopped. This might
@@ -1045,7 +1101,7 @@
 
 Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
 fine, as long as you do not mind that the priority value you query might
-or might not have been adjusted to be within valid range.
+or might not have been clamped to the valid range.
 
 =item ev_invoke (loop, ev_TYPE *watcher, int revents)
 
@@ -1296,8 +1352,10 @@
 monotonic clock option helps a lot here).
 
 The callback is guaranteed to be invoked only I<after> its timeout has
-passed, but if multiple timers become ready during the same loop iteration
-then order of execution is undefined.
+passed. If multiple timers become ready during the same loop iteration
+then the ones with earlier time-out values are invoked before ones with
+later time-out values (but this is no longer true when a callback calls
+C<ev_loop> recursively).
 
 =head3 Be smart about timeouts
 
@@ -1400,7 +1458,7 @@
          // callback was invoked, but there was some activity, re-arm
          // the watcher to fire in last_activity + 60, which is
          // guaranteed to be in the future, so "again" is positive:
-         w->again = timeout - now;
+         w->repeat = timeout - now;
          ev_timer_again (EV_A_ w);
        }
    }
@@ -1575,52 +1633,63 @@
 Periodic watchers are also timers of a kind, but they are very versatile
 (and unfortunately a bit complex).
 
-Unlike C<ev_timer>'s, they are not based on real time (or relative time)
-but on wall clock time (absolute time). You can tell a periodic watcher
-to trigger after some specific point in time. For example, if you tell a
-periodic watcher to trigger in 10 seconds (by specifying e.g. C<ev_now ()
-+ 10.>, that is, an absolute time not a delay) and then reset your system
-clock to January of the previous year, then it will take more than year
-to trigger the event (unlike an C<ev_timer>, which would still trigger
-roughly 10 seconds later as it uses a relative timeout).
-
-C<ev_periodic>s can also be used to implement vastly more complex timers,
-such as triggering an event on each "midnight, local time", or other
-complicated rules.
+Unlike C<ev_timer>, periodic watchers are not based on real time (or
+relative time, the physical time that passes) but on wall clock time
+(absolute time, the thing you can read on your calender or clock). The
+difference is that wall clock time can run faster or slower than real
+time, and time jumps are not uncommon (e.g. when you adjust your
+wrist-watch).
+
+You can tell a periodic watcher to trigger after some specific point
+in time: for example, if you tell a periodic watcher to trigger "in 10
+seconds" (by specifying e.g. C<ev_now () + 10.>, that is, an absolute time
+not a delay) and then reset your system clock to January of the previous
+year, then it will take a year or more to trigger the event (unlike an
+C<ev_timer>, which would still trigger roughly 10 seconds after starting
+it, as it uses a relative timeout).
+
+C<ev_periodic> watchers can also be used to implement vastly more complex
+timers, such as triggering an event on each "midnight, local time", or
+other complicated rules. This cannot be done with C<ev_timer> watchers, as
+those cannot react to time jumps.
 
 As with timers, the callback is guaranteed to be invoked only when the
-time (C<at>) has passed, but if multiple periodic timers become ready
-during the same loop iteration, then order of execution is undefined.
+point in time where it is supposed to trigger has passed. If multiple
+timers become ready during the same loop iteration then the ones with
+earlier time-out values are invoked before ones with later time-out values
+(but this is no longer true when a callback calls C<ev_loop> recursively).
 
 =head3 Watcher-Specific Functions and Data Members
 
 =over 4
 
-=item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)
+=item ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)
 
-=item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)
+=item ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb)
 
-Lots of arguments, lets sort it out... There are basically three modes of
+Lots of arguments, let's sort it out... There are basically three modes of
 operation, and we will explain them from simplest to most complex:
 
 =over 4
 
-=item * absolute timer (at = time, interval = reschedule_cb = 0)
+=item * absolute timer (offset = absolute time, interval = 0, reschedule_cb = 0)
 
 In this configuration the watcher triggers an event after the wall clock
-time C<at> has passed. It will not repeat and will not adjust when a time
-jump occurs, that is, if it is to be run at January 1st 2011 then it will
-only run when the system clock reaches or surpasses this time.
+time C<offset> has passed. It will not repeat and will not adjust when a
+time jump occurs, that is, if it is to be run at January 1st 2011 then it
+will be stopped and invoked when the system clock reaches or surpasses
+this point in time.
 
-=item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)
+=item * repeating interval timer (offset = offset within interval, interval > 0, reschedule_cb = 0)
 
 In this mode the watcher will always be scheduled to time out at the next
-C<at + N * interval> time (for some integer N, which can also be negative)
-and then repeat, regardless of any time jumps.
+C<offset + N * interval> time (for some integer N, which can also be
+negative) and then repeat, regardless of any time jumps. The C<offset>
+argument is merely an offset into the C<interval> periods.
 
 This can be used to create timers that do not drift with respect to the
-system clock, for example, here is a C<ev_periodic> that triggers each
-hour, on the hour:
+system clock, for example, here is an C<ev_periodic> that triggers each
+hour, on the hour (with respect to UTC):
 
    ev_periodic_set (&periodic, 0., 3600., 0);
 
@@ -1631,9 +1700,9 @@
 
 Another way to think about it (for the mathematically inclined) is that
 C<ev_periodic> will try to run the callback in this mode at the next possible
-time where C<time = at (mod interval)>, regardless of any time jumps.
+time where C<time = offset (mod interval)>, regardless of any time jumps.
 
-For numerical stability it is preferable that the C<at> value is near
+For numerical stability it is preferable that the C<offset> value is near
 C<ev_now ()> (the current time), but there is no range requirement for
 this value, and in fact is often specified as zero.
 
@@ -1642,15 +1711,16 @@
 will of course deteriorate. Libev itself tries to be exact to be about one
 millisecond (if the OS supports it and the machine is fast enough).
 
-=item * manual reschedule mode (at and interval ignored, reschedule_cb = callback)
+=item * manual reschedule mode (offset ignored, interval ignored, reschedule_cb = callback)
 
-In this mode the values for C<interval> and C<at> are both being
+In this mode the values for C<interval> and C<offset> are both being
 ignored. Instead, each time the periodic watcher gets scheduled, the
 reschedule callback will be called with the watcher as first, and the
 current time as second argument.
 
-NOTE: I<This callback MUST NOT stop or destroy any periodic watcher,
-ever, or make ANY event loop modifications whatsoever>.
+NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, ever,
+or make ANY other event loop modifications whatsoever, unless explicitly
+allowed by documentation here>.
 
 If you need to stop it, return C<now + 1e30> (or so, fudge fudge) and stop
 it afterwards (e.g. by starting an C<ev_prepare> watcher, which is the
@@ -1690,13 +1760,16 @@
 
 =item ev_tstamp ev_periodic_at (ev_periodic *)
 
-When active, returns the absolute time that the watcher is supposed to
-trigger next.
+When active, returns the absolute time that the watcher is supposed
+to trigger next. This is not the same as the C<offset> argument to
+C<ev_periodic_set>, but indeed works even in interval and manual
+rescheduling modes.
 
 =item ev_tstamp offset [read-write]
 
 When repeating, this contains the offset value, otherwise this is the
-absolute point in time (the C<at> value passed to C<ev_periodic_set>).
+absolute point in time (the C<offset> value passed to C<ev_periodic_set>,
+although libev might modify this value for better numerical stability).
 
 Can be modified any time, but changes only take effect when the periodic
 timer fires or C<ev_periodic_again> is being called.
@@ -1912,35 +1985,38 @@
 =head2 C<ev_stat> - did the file attributes just change?
 
 This watches a file system path for attribute changes. That is, it calls
-C<stat> regularly (or when the OS says it changed) and sees if it changed
-compared to the last time, invoking the callback if it did.
+C<stat> on that path in regular intervals (or when the OS says it changed)
+and sees if it changed compared to the last time, invoking the callback if
+it did.
 
 The path does not need to exist: changing from "path exists" to "path does
-not exist" is a status change like any other. The condition "path does
-not exist" is signified by the C<st_nlink> field being zero (which is
-otherwise always forced to be at least one) and all the other fields of
-the stat buffer having unspecified contents.
-
-The path I<should> be absolute and I<must not> end in a slash. If it is
-relative and your working directory changes, the behaviour is undefined.
-
-Since there is no standard kernel interface to do this, the portable
-implementation simply calls C<stat (2)> regularly on the path to see if
-it changed somehow. You can specify a recommended polling interval for
-this case. If you specify a polling interval of C<0> (highly recommended!)
-then a I<suitable, unspecified default> value will be used (which
-you can expect to be around five seconds, although this might change
-dynamically). Libev will also impose a minimum interval which is currently
-around C<0.1>, but thats usually overkill.
+not exist" is a status change like any other. The condition "path does not
+exist" (or more correctly "path cannot be stat'ed") is signified by the
+C<st_nlink> field being zero (which is otherwise always forced to be at
+least one) and all the other fields of the stat buffer having unspecified
+contents.
+
+The path I<must not> end in a slash or contain special components such as
+C<.> or C<..>. The path I<should> be absolute: If it is relative and
+your working directory changes, then the behaviour is undefined.
+
+Since there is no portable change notification interface available, the
+portable implementation simply calls C<stat(2)> regularly on the path
+to see if it changed somehow. You can specify a recommended polling
+interval for this case. If you specify a polling interval of C<0> (highly
+recommended!) then a I<suitable, unspecified default> value will be used
+(which you can expect to be around five seconds, although this might
+change dynamically). Libev will also impose a minimum interval which is
+currently around C<0.1>, but that's usually overkill.
 
 This watcher type is not meant for massive numbers of stat watchers,
 as even with OS-supported change notifications, this can be
 resource-intensive.
 
 At the time of this writing, the only OS-specific interface implemented
-is the Linux inotify interface (implementing kqueue support is left as
-an exercise for the reader. Note, however, that the author sees no way
-of implementing C<ev_stat> semantics with kqueue).
+is the Linux inotify interface (implementing kqueue support is left as an
+exercise for the reader. Note, however, that the author sees no way of
+implementing C<ev_stat> semantics with kqueue, except as a hint).
 
 =head3 ABI Issues (Largefile Support)
 
@@ -1951,7 +2027,7 @@
 use 64 bit file offsets the programs will fail. In that case you have to
 compile libev with the same flags to get binary compatibility. This is
 obviously the case with any flags that change the ABI, but the problem is
-most noticeably disabled with ev_stat and large file support.
+most noticeably displayed with ev_stat and large file support.
 
 The solution for this is to lobby your distribution maker to make large
 file interfaces available by default (as e.g. FreeBSD does) and not
@@ -1961,28 +2037,48 @@
 
 =head3 Inotify and Kqueue
 
-When C<inotify (7)> support has been compiled into libev (generally
-only available with Linux 2.6.25 or above due to bugs in earlier
-implementations) and present at runtime, it will be used to speed up
-change detection where possible. The inotify descriptor will be created
-lazily when the first C<ev_stat> watcher is being started.
+When C<inotify (7)> support has been compiled into libev and present at
+runtime, it will be used to speed up change detection where possible. The
+inotify descriptor will be created lazily when the first C<ev_stat>
+watcher is being started.
 
 Inotify presence does not change the semantics of C<ev_stat> watchers
 except that changes might be detected earlier, and in some cases, to avoid
 making regular C<stat> calls. Even in the presence of inotify support
 there are many cases where libev has to resort to regular C<stat> polling,
-but as long as the path exists, libev usually gets away without polling.
+but as long as kernel 2.6.25 or newer is used (2.6.24 and older have too
+many bugs), the path exists (i.e. stat succeeds), and the path resides on
+a local filesystem (libev currently assumes only ext2/3, jfs, reiserfs and
+xfs are fully working) libev usually gets away without polling.
 
 There is no support for kqueue, as apparently it cannot be used to
 implement this functionality, due to the requirement of having a file
 descriptor open on the object at all times, and detecting renames, unlinks
 etc. is difficult.
 
+=head3 C<stat ()> is a synchronous operation
+
+Libev doesn't normally do any kind of I/O itself, and so is not blocking
+the process. The exception are C<ev_stat> watchers - those call C<stat
+()>, which is a synchronous operation.
+
+For local paths, this usually doesn't matter: unless the system is very
+busy or the intervals between stat's are large, a stat call will be fast,
+as the path data is usually in memory already (except when starting the
+watcher).
+
+For networked file systems, calling C<stat ()> can block an indefinite
+time due to network issues, and even under good conditions, a stat call
+often takes multiple milliseconds.
+
+Therefore, it is best to avoid using C<ev_stat> watchers on networked
+paths, although this is fully supported by libev.
+
 =head3 The special problem of stat time resolution
 
-The C<stat ()> system call only supports full-second resolution portably, and
-even on systems where the resolution is higher, most file systems still
-only support whole seconds.
+The C<stat ()> system call only supports full-second resolution portably,
+and even on systems where the resolution is higher, most file systems
+still only support whole seconds.
 
 That means that, if the time is the only thing that changes, you can
 easily miss updates: on the first update, C<ev_stat> detects a change and
@@ -2135,7 +2231,7 @@
 
 =over 4
 
-=item ev_idle_init (ev_signal *, callback)
+=item ev_idle_init (ev_idle *, callback)
 
 Initialises and configures the idle watcher - it has no parameters of any
 kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
@@ -2384,24 +2480,20 @@
 this case you would put all the high priority stuff in one loop and all
 the rest in a second one, and embed the second one in the first.
 
-As long as the watcher is active, the callback will be invoked every time
-there might be events pending in the embedded loop. The callback must then
-call C<ev_embed_sweep (mainloop, watcher)> to make a single sweep and invoke
-their callbacks (you could also start an idle watcher to give the embedded
-loop strictly lower priority for example). You can also set the callback
-to C<0>, in which case the embed watcher will automatically execute the
-embedded loop sweep.
-
-As long as the watcher is started it will automatically handle events. The
-callback will be invoked whenever some events have been handled. You can
-set the callback to C<0> to avoid having to specify one if you are not
-interested in that.
-
-Also, there have not currently been made special provisions for forking:
-when you fork, you not only have to call C<ev_loop_fork> on both loops,
-but you will also have to stop and restart any C<ev_embed> watchers
-yourself - but you can use a fork watcher to handle this automatically,
-and future versions of libev might do just that.
+As long as the watcher is active, the callback will be invoked every
+time there might be events pending in the embedded loop. The callback
+must then call C<ev_embed_sweep (mainloop, watcher)> to make a single
+sweep and invoke their callbacks (the callback doesn't need to invoke the
+C<ev_embed_sweep> function directly, it could also start an idle watcher
+to give the embedded loop strictly lower priority for example).
+
+You can also set the callback to C<0>, in which case the embed watcher
+will automatically execute the embedded loop sweep whenever necessary.
+
+Fork detection will be handled transparently while the C<ev_embed> watcher
+is active, i.e., the embedded loop will automatically be forked when the
+embedding loop forks. In other cases, the user is responsible for calling
+C<ev_loop_fork> on the embedded loop.
 
 Unfortunately, not all backends are embeddable: only the ones returned by
 C<ev_embeddable_backends> are, which, unfortunately, does not include any
@@ -2631,7 +2723,7 @@
 =item ev_async_init (ev_async *, callback)
 
 Initialises and configures the async watcher - it has no parameters of any
-kind. There is a C<ev_asynd_set> macro, but using it is utterly pointless,
+kind. There is a C<ev_async_set> macro, but using it is utterly pointless,
 trust me.
 
 =item ev_async_send (loop, ev_async *)
@@ -2642,9 +2734,14 @@
 similar contexts (see the discussion of C<EV_ATOMIC_T> in the embedding
 section below on what exactly this means).
 
-This call incurs the overhead of a system call only once per loop iteration,
-so while the overhead might be noticeable, it doesn't apply to repeated
-calls to C<ev_async_send>.
+Note that, as with other watchers in libev, multiple events might get
+compressed into a single callback invocation (another way to look at this
+is that C<ev_async> watchers are level-triggered, set on C<ev_async_send>,
+reset when the event loop detects that).
+
+This call incurs the overhead of a system call only once per event loop
+iteration, so while the overhead might be noticeable, it doesn't apply to
+repeated calls to C<ev_async_send> for the same event loop.
 
 =item bool = ev_async_pending (ev_async *)
 
@@ -2657,8 +2754,10 @@
 it will reset the flag again. C<ev_async_pending> can be used to very
 quickly check whether invoking the loop might be a good idea.
 
-Not that this does I<not> check whether the watcher itself is pending, only
-whether it has been requested to make this watcher pending.
+Not that this does I<not> check whether the watcher itself is pending,
+only whether it has been requested to make this watcher pending: there
+is a time window between the event loop checking and resetting the async
+notification, and the callback being invoked.
 
 =back
 
@@ -2847,6 +2946,36 @@
    ev::io iow;
    iow.set <myclass, &myclass::io_cb> (&obj);
 
+=item w->set (object *)
+
+This is an B<experimental> feature that might go away in a future version.
+
+This is a variation of a method callback - leaving out the method to call
+will default the method to C<operator ()>, which makes it possible to use
+functor objects without having to manually specify the C<operator ()> all
+the time. Incidentally, you can then also leave out the template argument
+list.
+
+The C<operator ()> method prototype must be C<void operator ()(watcher &w,
+int revents)>.
+
+See the method-C<set> above for more details.
+
+Example: use a functor object as callback.
+
+   struct myfunctor
+   {
+     void operator() (ev::io &w, int revents)
+     {
+       ...
+     }
+   }
+    
+   myfunctor f;
+
+   ev::io w;
+   w.set (&f);
+
 =item w->set<function> (void *data = 0)
 
 Also sets a callback, but uses a static method or plain function as
@@ -2942,11 +3071,7 @@
 =item Python
 
 Python bindings can be found at L<http://code.google.com/p/pyev/>. It
-seems to be quite complete and well-documented. Note, however, that the
-patch they require for libev is outright dangerous as it breaks the ABI
-for everybody else, and therefore, should never be applied in an installed
-libev (if python requires an incompatible ABI then it needs to embed
-libev).
+seems to be quite complete and well-documented.
 
 =item Ruby
 
@@ -2955,6 +3080,14 @@
 more on top of it. It can be found via gem servers. Its homepage is at
 L<http://rev.rubyforge.org/>.
 
+Roger Pack reports that using the link order C<-lws2_32 -lmsvcrt-ruby-190>
+makes rev work even on mingw.
+
+=item Haskell
+
+A haskell binding to libev is available at
+L<http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hlibev>.
+
 =item D
 
 Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to
@@ -3074,7 +3207,7 @@
    #include "ev.h"
 
 Both header files and implementation files can be compiled with a C++
-compiler (at least, thats a stated goal, and breakage will be treated
+compiler (at least, that's a stated goal, and breakage will be treated
 as a bug).
 
 You need the following files in your source tree, or in a directory
@@ -3140,24 +3273,40 @@
 supported). It will also not define any of the structs usually found in
 F<event.h> that are not directly supported by the libev core alone.
 
+In stanbdalone mode, libev will still try to automatically deduce the
+configuration, but has to be more conservative.
+
 =item EV_USE_MONOTONIC
 
 If defined to be C<1>, libev will try to detect the availability of the
-monotonic clock option at both compile time and runtime. Otherwise no use
-of the monotonic clock option will be attempted. If you enable this, you
-usually have to link against librt or something similar. Enabling it when
-the functionality isn't available is safe, though, although you have
+monotonic clock option at both compile time and runtime. Otherwise no
+use of the monotonic clock option will be attempted. If you enable this,
+you usually have to link against librt or something similar. Enabling it
+when the functionality isn't available is safe, though, although you have
 to make sure you link against any libraries where the C<clock_gettime>
-function is hiding in (often F<-lrt>).
+function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>.
 
 =item EV_USE_REALTIME
 
 If defined to be C<1>, libev will try to detect the availability of the
-real-time clock option at compile time (and assume its availability at
-runtime if successful). Otherwise no use of the real-time clock option will
-be attempted. This effectively replaces C<gettimeofday> by C<clock_get
-(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
-note about libraries in the description of C<EV_USE_MONOTONIC>, though.
+real-time clock option at compile time (and assume its availability
+at runtime if successful). Otherwise no use of the real-time clock
+option will be attempted. This effectively replaces C<gettimeofday>
+by C<clock_get (CLOCK_REALTIME, ...)> and will not normally affect
+correctness. See the note about libraries in the description of
+C<EV_USE_MONOTONIC>, though. Defaults to the opposite value of
+C<EV_USE_CLOCK_SYSCALL>.
+
+=item EV_USE_CLOCK_SYSCALL
+
+If defined to be C<1>, libev will try to use a direct syscall instead
+of calling the system-provided C<clock_gettime> function. This option
+exists because on GNU/Linux, C<clock_gettime> is in C<librt>, but C<librt>
+unconditionally pulls in C<libpthread>, slowing down single-threaded
+programs needlessly. Using a direct syscall is slightly slower (in
+theory), because no optimised vdso implementation can be used, but avoids
+the pthread dependency. Defaults to C<1> on GNU/Linux with glibc 2.x or
+higher, as it simplifies linking (no need for C<-lrt>).
 
 =item EV_USE_NANOSLEEP
 
@@ -3183,11 +3332,11 @@
 
 If defined to C<1>, then the select backend will use the system C<fd_set>
 structure. This is useful if libev doesn't compile due to a missing
-C<NFDBITS> or C<fd_mask> definition or it mis-guesses the bitset layout on
-exotic systems. This usually limits the range of file descriptors to some
-low limit such as 1024 or might have other limitations (winsocket only
-allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation, might
-influence the size of the C<fd_set> used.
+C<NFDBITS> or C<fd_mask> definition or it mis-guesses the bitset layout
+on exotic systems. This usually limits the range of file descriptors to
+some low limit such as 1024 or might have other limitations (winsocket
+only allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation,
+configures the maximum size of the C<fd_set>.
 
 =item EV_SELECT_IS_WINSOCKET
 
@@ -3556,7 +3705,7 @@
 
 Care has been taken to ensure that libev does not keep local state inside
 C<ev_loop>, and other calls do not usually allow for coroutine switches as
-they do not clal any callbacks.
+they do not call any callbacks.
 
 =head2 COMPILER WARNINGS
 
@@ -3600,7 +3749,7 @@
    ==2274==    still reachable: 256 bytes in 1 blocks.
 
 Then there is no memory leak, just as memory accounted to global variables
-is not a memleak - the memory is still being refernced, and didn't leak.
+is not a memleak - the memory is still being referenced, and didn't leak.
 
 Similarly, under some circumstances, valgrind might report kernel bugs
 as if it were a bug in libev (e.g. in realloc or in the poll backend,
@@ -3848,5 +3997,5 @@
 
 =head1 AUTHOR
 
-Marc Lehmann <libev@schmorp.de>.
+Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.