*** empty log message ***

[software/libev.git] / ev.pod

diff --git a/ev.pod b/ev.pod
index cc478bd5fe6848984dfc050dca81f00a8f9ec98c..ed0ac1b9a519e1716e2ceb45874ef263e429dbd3 100644 (file)
--- a/ev.pod
+++ b/ev.pod
@@ -6,6 +6,48 @@ libev - a high performance full-featured event loop written in C
 
   #include <ev.h>
 
 
   #include <ev.h>
 

+=head1 EXAMPLE PROGRAM
+
+  #include <ev.h>
+
+  ev_io stdin_watcher;
+  ev_timer timeout_watcher;
+
+  /* called when data readable on stdin */
+  static void
+  stdin_cb (EV_P_ struct ev_io *w, int revents)
+  {
+    /* puts ("stdin ready"); */
+    ev_io_stop (EV_A_ w); /* just a syntax example */
+    ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */
+  }
+
+  static void
+  timeout_cb (EV_P_ struct ev_timer *w, int revents)
+  {
+    /* puts ("timeout"); */
+    ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
+  }
+
+  int
+  main (void)
+  {
+    struct ev_loop *loop = ev_default_loop (0);
+
+    /* initialise an io watcher, then start it */
+    ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
+    ev_io_start (loop, &stdin_watcher);
+
+    /* simple non-repeating 5.5 second timeout */
+    ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+    ev_timer_start (loop, &timeout_watcher);
+
+    /* loop till timeout or data ready */
+    ev_loop (loop, 0);
+
+    return 0;
+  }
+

 =head1 DESCRIPTION
 
 Libev is an event loop: you register interest in certain events (such as a
 =head1 DESCRIPTION
 
 Libev is an event loop: you register interest in certain events (such as a


@@ -23,23 +65,29 @@ watcher.
 
 =head1 FEATURES
 
 
 =head1 FEATURES
 

-Libev supports select, poll, the linux-specific epoll and the bsd-specific
-kqueue mechanisms for file descriptor events, relative timers, absolute
-timers with customised rescheduling, signal events, process status change
-events (related to SIGCHLD), and event watchers dealing with the event
-loop mechanism itself (idle, prepare and check watchers). It also is quite
-fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing
-it to libevent for example).
+Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the
+BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
+for file descriptor events (C<ev_io>), the Linux C<inotify> interface
+(for C<ev_stat>), relative timers (C<ev_timer>), absolute timers
+with customised rescheduling (C<ev_periodic>), synchronous signals
+(C<ev_signal>), process status change events (C<ev_child>), and event
+watchers dealing with the event loop mechanism itself (C<ev_idle>,
+C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as
+file watchers (C<ev_stat>) and even limited support for fork events
+(C<ev_fork>).
+
+It also is quite fast (see this
+L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent
+for example).

 
 =head1 CONVENTIONS
 
 
 =head1 CONVENTIONS
 

-Libev is very configurable. In this manual the default configuration
-will be described, which supports multiple event loops. For more info
-about various configuration options please have a look at the file
-F<README.embed> in the libev distribution. If libev was configured without
-support for multiple event loops, then all functions taking an initial
-argument of name C<loop> (which is always of type C<struct ev_loop *>)
-will not have this argument.
+Libev is very configurable. In this manual the default configuration will
+be described, which supports multiple event loops. For more info about
+various configuration options please have a look at B<EMBED> section in
+this manual. If libev was configured without support for multiple event
+loops, then all functions taking an initial argument of name C<loop>
+(which is always of type C<struct ev_loop *>) will not have this argument.

 
 =head1 TIME REPRESENTATION
 
 
 =head1 TIME REPRESENTATION
 


@@ -50,7 +98,6 @@ called C<ev_tstamp>, which is what you should use too. It usually aliases
 to the C<double> type in C, and when you need to do any calculations on
 it, you should treat it as such.
 
 to the C<double> type in C, and when you need to do any calculations on
 it, you should treat it as such.
 

-

 =head1 GLOBAL FUNCTIONS
 
 These functions can be called anytime, even before initialising the
 =head1 GLOBAL FUNCTIONS
 
 These functions can be called anytime, even before initialising the


@@ -79,8 +126,8 @@ as this indicates an incompatible change.  Minor versions are usually
 compatible to older versions, so a larger minor version alone is usually
 not a problem.
 
 compatible to older versions, so a larger minor version alone is usually
 not a problem.
 

-Example: make sure we haven't accidentally been linked against the wrong
-version:
+Example: Make sure we haven't accidentally been linked against the wrong
+version.

 
   assert (("libev version mismatch",
            ev_version_major () == EV_VERSION_MAJOR
 
   assert (("libev version mismatch",
            ev_version_major () == EV_VERSION_MAJOR


@@ -120,21 +167,22 @@ See the description of C<ev_embed> watchers for more info.
 
 =item ev_set_allocator (void *(*cb)(void *ptr, long size))
 
 
 =item ev_set_allocator (void *(*cb)(void *ptr, long size))
 

-Sets the allocation function to use (the prototype is similar to the
-realloc C function, the semantics are identical). It is used to allocate
-and free memory (no surprises here). If it returns zero when memory
-needs to be allocated, the library might abort or take some potentially
-destructive action. The default is your system realloc function.
+Sets the allocation function to use (the prototype is similar - the
+semantics is identical - to the realloc C function). It is used to
+allocate and free memory (no surprises here). If it returns zero when
+memory needs to be allocated, the library might abort or take some
+potentially destructive action. The default is your system realloc
+function.

 
 You could override this function in high-availability programs to, say,
 free some memory if it cannot allocate memory, to use a special allocator,
 or even to sleep a while and retry until some memory is available.
 
 
 You could override this function in high-availability programs to, say,
 free some memory if it cannot allocate memory, to use a special allocator,
 or even to sleep a while and retry until some memory is available.
 

-Example: replace the libev allocator with one that waits a bit and then
-retries: better than mine).
+Example: Replace the libev allocator with one that waits a bit and then
+retries).

 
    static void *
 
    static void *

-   persistent_realloc (void *ptr, long size)
+   persistent_realloc (void *ptr, size_t size)

    {
      for (;;)
        {
    {
      for (;;)
        {


@@ -160,7 +208,7 @@ matter what, when it returns. That is, libev will generally retry the
 requested operation, or, if the condition doesn't go away, do bad stuff
 (such as abort).
 
 requested operation, or, if the condition doesn't go away, do bad stuff
 (such as abort).
 

-Example: do the same thing as libev does internally:
+Example: This is basically the same thing that libev does internally, too.

 
    static void
    fatal_error (const char *msg)
 
    static void
    fatal_error (const char *msg)


@@ -220,6 +268,26 @@ 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
 around bugs.
 
 useful to try out specific backends to test their performance, or to work
 around bugs.
 

+=item C<EVFLAG_FORKCHECK>
+
+Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after
+a fork, you can also make libev check for a fork in each iteration by
+enabling this flag.
+
+This works by calling C<getpid ()> on every iteration of the loop,
+and thus this might slow down your event loop if you do a lot of loop
+iterations and little real work, but is usually not noticeable (on my
+Linux system for example, C<getpid> is actually a simple 5-insn sequence
+without a syscall and thus I<very> fast, but my Linux system also has
+C<pthread_atfork> which is even faster).
+
+The big advantage of this flag is that you can forget about fork (and
+forget about forgetting to tell libev about forking) when you use this
+flag.
+
+This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS>
+environment variable.
+

 =item C<EVBACKEND_SELECT>  (value 1, portable select backend)
 
 This is your standard select(2) backend. Not I<completely> standard, as
 =item C<EVBACKEND_SELECT>  (value 1, portable select backend)
 
 This is your standard select(2) backend. Not I<completely> standard, as


@@ -316,7 +384,7 @@ always distinct from the default loop. Unlike the default loop, it cannot
 handle signal and child watchers, and attempts to do so will be greeted by
 undefined behaviour (or a failed assertion if assertions are enabled).
 
 handle signal and child watchers, and attempts to do so will be greeted by
 undefined behaviour (or a failed assertion if assertions are enabled).
 

-Example: try to create a event loop that uses epoll and nothing else.
+Example: Try to create a event loop that uses epoll and nothing else.

 
   struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
   if (!epoller)
 
   struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
   if (!epoller)


@@ -425,7 +493,7 @@ Here are the gory details of what C<ev_loop> does:
    - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
      were used, return, otherwise continue with step *.
 
    - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
      were used, return, otherwise continue with step *.
 

-Example: queue some jobs and then loop until no events are outsanding
+Example: Queue some jobs and then loop until no events are outsanding

 anymore.
 
    ... queue jobs here, make sure they register event watchers as long
 anymore.
 
    ... queue jobs here, make sure they register event watchers as long


@@ -455,18 +523,18 @@ 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>.
 
 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>.
 

-Example: create a signal watcher, but keep it from keeping C<ev_loop>
+Example: Create a signal watcher, but keep it from keeping C<ev_loop>

 running when nothing else is active.
 
 running when nothing else is active.
 

-  struct dv_signal exitsig;
+  struct ev_signal exitsig;

   ev_signal_init (&exitsig, sig_cb, SIGINT);
   ev_signal_init (&exitsig, sig_cb, SIGINT);

-  ev_signal_start (myloop, &exitsig);
-  evf_unref (myloop);
+  ev_signal_start (loop, &exitsig);
+  evf_unref (loop);

 
 

-Example: for some weird reason, unregister the above signal handler again.
+Example: For some weird reason, unregister the above signal handler again.

 
 

-  ev_ref (myloop);
-  ev_signal_stop (myloop, &exitsig);
+  ev_ref (loop);
+  ev_signal_stop (loop, &exitsig);

 
 =back
 
 
 =back
 


@@ -567,6 +635,15 @@ many watchers as they want, and all of them will be taken into account
 (for example, a C<ev_prepare> watcher might start an idle watcher to keep
 C<ev_loop> from blocking).
 
 (for example, a C<ev_prepare> watcher might start an idle watcher to keep
 C<ev_loop> from blocking).
 

+=item C<EV_EMBED>
+
+The embedded event loop specified in the C<ev_embed> watcher needs attention.
+
+=item C<EV_FORK>
+
+The event loop has been resumed in the child process after fork (see
+C<ev_fork>).
+

 =item C<EV_ERROR>
 
 An unspecified error has occured, the watcher has been stopped. This might
 =item C<EV_ERROR>
 
 An unspecified error has occured, the watcher has been stopped. This might


@@ -650,7 +727,7 @@ is pending (but not active) you must not call an init function on it (but
 C<ev_TYPE_set> is safe) and you must make sure the watcher is available to
 libev (e.g. you cnanot C<free ()> it).
 
 C<ev_TYPE_set> is safe) and you must make sure the watcher is available to
 libev (e.g. you cnanot C<free ()> it).
 

-=item callback = ev_cb (ev_TYPE *watcher)
+=item callback ev_cb (ev_TYPE *watcher)

 
 Returns the callback currently set on the watcher.
 
 
 Returns the callback currently set on the watcher.
 


@@ -688,8 +765,37 @@ can cast it back to your own type:
     ...
   }
 
     ...
   }
 

-More interesting and less C-conformant ways of catsing your callback type
-have been omitted....
+More interesting and less C-conformant ways of casting your callback type
+instead have been omitted.
+
+Another common scenario is having some data structure with multiple
+watchers:
+
+  struct my_biggy
+  {
+    int some_data;
+    ev_timer t1;
+    ev_timer t2;
+  }
+
+In this case getting the pointer to C<my_biggy> is a bit more complicated,
+you need to use C<offsetof>:
+
+  #include <stddef.h>
+
+  static void
+  t1_cb (EV_P_ struct ev_timer *w, int revents)
+  {
+    struct my_biggy big = (struct my_biggy *
+      (((char *)w) - offsetof (struct my_biggy, t1));
+  }
+
+  static void
+  t2_cb (EV_P_ struct ev_timer *w, int revents)
+  {
+    struct my_biggy big = (struct my_biggy *
+      (((char *)w) - offsetof (struct my_biggy, t2));
+  }

 
 
 =head1 WATCHER TYPES
 
 
 =head1 WATCHER TYPES


@@ -768,9 +874,9 @@ The events being watched.
 
 =back
 
 
 =back
 

-Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well
+Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well

 readable, but only once. Since it is likely line-buffered, you could
 readable, but only once. Since it is likely line-buffered, you could

-attempt to read a whole line in the callback:
+attempt to read a whole line in the callback.

 
   static void
   stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
 
   static void
   stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)


@@ -832,23 +938,25 @@ timer will not fire more than once per event loop iteration.
 This will act as if the timer timed out and restart it again if it is
 repeating. The exact semantics are:
 
 This will act as if the timer timed out and restart it again if it is
 repeating. The exact semantics are:
 

-If the timer is started but nonrepeating, stop it.
+If the timer is pending, its pending status is cleared.

 
 

-If the timer is repeating, either start it if necessary (with the repeat
-value), or reset the running timer to the repeat value.
+If the timer is started but nonrepeating, stop it (as if it timed out).
+
+If the timer is repeating, either start it if necessary (with the
+C<repeat> value), or reset the running timer to the C<repeat> value.

 
 This sounds a bit complicated, but here is a useful and typical
 
 This sounds a bit complicated, but here is a useful and typical

-example: Imagine you have a tcp connection and you want a so-called
-idle timeout, that is, you want to be called when there have been,
-say, 60 seconds of inactivity on the socket. The easiest way to do
-this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling
+example: Imagine you have a tcp connection and you want a so-called idle
+timeout, that is, you want to be called when there have been, say, 60
+seconds of inactivity on the socket. The easiest way to do this is to
+configure an C<ev_timer> with a C<repeat> value of C<60> and then call

 C<ev_timer_again> each time you successfully read or write some data. If
 you go into an idle state where you do not expect data to travel on the
 C<ev_timer_again> each time you successfully read or write some data. If
 you go into an idle state where you do not expect data to travel on the

-socket, you can stop the timer, and again will automatically restart it if
-need be.
+socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
+automatically restart it if need be.

 
 

-You can also ignore the C<after> value and C<ev_timer_start> altogether
-and only ever use the C<repeat> value:
+That means you can ignore the C<after> value and C<ev_timer_start>
+altogether and only ever use the C<repeat> value and C<ev_timer_again>:

 
    ev_timer_init (timer, callback, 0., 5.);
    ev_timer_again (loop, timer);
 
    ev_timer_init (timer, callback, 0., 5.);
    ev_timer_again (loop, timer);


@@ -859,8 +967,8 @@ and only ever use the C<repeat> value:
    timer->again = 10.;
    ev_timer_again (loop, timer);
 
    timer->again = 10.;
    ev_timer_again (loop, timer);
 

-This is more efficient then stopping/starting the timer eahc time you want
-to modify its timeout value.
+This is more slightly efficient then stopping/starting the timer each time
+you want to modify its timeout value.

 
 =item ev_tstamp repeat [read-write]
 
 
 =item ev_tstamp repeat [read-write]
 


@@ -870,7 +978,7 @@ which is also when any modifications are taken into account.
 
 =back
 
 
 =back
 

-Example: create a timer that fires after 60 seconds.
+Example: Create a timer that fires after 60 seconds.

 
   static void
   one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
 
   static void
   one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)


@@ -882,7 +990,7 @@ Example: create a timer that fires after 60 seconds.
   ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
   ev_timer_start (loop, &mytimer);
 
   ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
   ev_timer_start (loop, &mytimer);
 

-Example: create a timeout timer that times out after 10 seconds of
+Example: Create a timeout timer that times out after 10 seconds of

 inactivity.
 
   static void
 inactivity.
 
   static void


@@ -1017,7 +1125,7 @@ the periodic timer fires or C<ev_periodic_again> is being called.
 
 =back
 
 
 =back
 

-Example: call a callback every hour, or, more precisely, whenever the
+Example: Call a callback every hour, or, more precisely, whenever the

 system clock is divisible by 3600. The callback invocation times have
 potentially a lot of jittering, but good long-term stability.
 
 system clock is divisible by 3600. The callback invocation times have
 potentially a lot of jittering, but good long-term stability.
 


@@ -1031,7 +1139,7 @@ potentially a lot of jittering, but good long-term stability.
   ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
   ev_periodic_start (loop, &hourly_tick);
 
   ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
   ev_periodic_start (loop, &hourly_tick);
 

-Example: the same as above, but use a reschedule callback to do it:
+Example: The same as above, but use a reschedule callback to do it:

 
   #include <math.h>
 
 
   #include <math.h>
 


@@ -1043,7 +1151,7 @@ Example: the same as above, but use a reschedule callback to do it:
 
   ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
 
 
   ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
 

-Example: call a callback every hour, starting now:
+Example: Call a callback every hour, starting now:

 
   struct ev_periodic hourly_tick;
   ev_periodic_init (&hourly_tick, clock_cb,
 
   struct ev_periodic hourly_tick;
   ev_periodic_init (&hourly_tick, clock_cb,


@@ -1114,7 +1222,7 @@ C<waitpid> and C<sys/wait.h> documentation for details).
 
 =back
 
 
 =back
 

-Example: try to exit cleanly on SIGINT and SIGTERM.
+Example: Try to exit cleanly on SIGINT and SIGTERM.

 
   static void
   sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
 
   static void
   sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)


@@ -1139,8 +1247,11 @@ 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.
 
 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 to do this, the portable implementation simply
 Since there is no standard to do this, the portable implementation simply

-calls C<stat (2)> regulalry on the path to see if it changed somehow. You
+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
 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


@@ -1152,8 +1263,13 @@ This watcher type is not meant for massive numbers of stat watchers,
 as even with OS-supported change notifications, this can be
 resource-intensive.
 
 as even with OS-supported change notifications, this can be
 resource-intensive.
 

-At the time of this writing, no specific OS backends are implemented, but
-if demand increases, at least a kqueue and inotify backend will be added.
+At the time of this writing, only the Linux inotify interface is
+implemented (implementing kqueue support is left as an exercise for the
+reader). Inotify will be used to give hints only and should not change the
+semantics of C<ev_stat> watchers, which means that libev sometimes needs
+to fall back to regular polling again even with inotify, but changes are
+usually detected immediately, and if the file exists there will be no
+polling.

 
 =over 4
 
 
 =over 4
 


@@ -1253,8 +1369,8 @@ believe me.
 
 =back
 
 
 =back
 

-Example: dynamically allocate an C<ev_idle>, start it, and in the
-callback, free it. Alos, use no error checking, as usual.
+Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
+callback, free it. Also, use no error checking, as usual.

 
   static void
   idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
 
   static void
   idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)


@@ -1343,7 +1459,8 @@ pseudo-code only of course:
   static void
   adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)
   {
   static void
   adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)
   {

-    int timeout = 3600000;truct pollfd fds [nfd];
+    int timeout = 3600000;
+    struct pollfd fds [nfd];

     // actual code will need to loop here and realloc etc.
     adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
 
     // actual code will need to loop here and realloc etc.
     adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
 


@@ -1472,6 +1589,27 @@ The embedded event loop.
 =back
 
 
 =back
 
 

+=head2 C<ev_fork> - the audacity to resume the event loop after a fork
+
+Fork watchers are called when a C<fork ()> was detected (usually because
+whoever is a good citizen cared to tell libev about it by calling
+C<ev_default_fork> or C<ev_loop_fork>). The invocation is done before the
+event loop blocks next and before C<ev_check> watchers are being called,
+and only in the child after the fork. If whoever good citizen calling
+C<ev_default_fork> cheats and calls it in the wrong process, the fork
+handlers will be invoked, too, of course.
+
+=over 4
+
+=item ev_fork_init (ev_signal *, callback)
+
+Initialises and configures the fork watcher - it has no parameters of any
+kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
+believe me.
+
+=back
+
+

 =head1 OTHER FUNCTIONS
 
 There are some other functions of possible interest. Described. Here. Now.
 =head1 OTHER FUNCTIONS
 
 There are some other functions of possible interest. Described. Here. Now.


@@ -1640,6 +1778,10 @@ C<ev_TYPE_again> function.
 
 Invokes C<ev_embed_sweep>.
 
 
 Invokes C<ev_embed_sweep>.
 

+=item w->update ()      C<ev::stat> only
+
+Invokes C<ev_stat_stat>.
+

 =back
 
 =back
 =back
 
 =back


@@ -1662,6 +1804,68 @@ the constructor.
     io.start (fd, ev::READ);
   }
 
     io.start (fd, ev::READ);
   }
 

+
+=head1 MACRO MAGIC
+
+Libev can be compiled with a variety of options, the most fundemantal is
+C<EV_MULTIPLICITY>. This option determines wether (most) functions and
+callbacks have an initial C<struct ev_loop *> argument.
+
+To make it easier to write programs that cope with either variant, the
+following macros are defined:
+
+=over 4
+
+=item C<EV_A>, C<EV_A_>
+
+This provides the loop I<argument> for functions, if one is required ("ev
+loop argument"). The C<EV_A> form is used when this is the sole argument,
+C<EV_A_> is used when other arguments are following. Example:
+
+  ev_unref (EV_A);
+  ev_timer_add (EV_A_ watcher);
+  ev_loop (EV_A_ 0);
+
+It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
+which is often provided by the following macro.
+
+=item C<EV_P>, C<EV_P_>
+
+This provides the loop I<parameter> for functions, if one is required ("ev
+loop parameter"). The C<EV_P> form is used when this is the sole parameter,
+C<EV_P_> is used when other parameters are following. Example:
+
+  // this is how ev_unref is being declared
+  static void ev_unref (EV_P);
+
+  // this is how you can declare your typical callback
+  static void cb (EV_P_ ev_timer *w, int revents)
+
+It declares a parameter C<loop> of type C<struct ev_loop *>, quite
+suitable for use with C<EV_A>.
+
+=item C<EV_DEFAULT>, C<EV_DEFAULT_>
+
+Similar to the other two macros, this gives you the value of the default
+loop, if multiple loops are supported ("ev loop default").
+
+=back
+
+Example: Declare and initialise a check watcher, utilising the above
+macros so it will work regardless of wether multiple loops are supported
+or not.
+
+  static void
+  check_cb (EV_P_ ev_timer *w, int revents)
+  {
+    ev_check_stop (EV_A_ w);
+  }
+
+  ev_check check;
+  ev_check_init (&check, check_cb);
+  ev_check_start (EV_DEFAULT_ &check);
+  ev_loop (EV_DEFAULT_ 0);
+

 =head1 EMBEDDING
 
 Libev can (and often is) directly embedded into host
 =head1 EMBEDDING
 
 Libev can (and often is) directly embedded into host


@@ -1710,7 +1914,7 @@ in your include path (e.g. in libev/ when using -Ilibev):
 
   ev_win32.c      required on win32 platforms only
 
 
   ev_win32.c      required on win32 platforms only
 

-  ev_select.c     only when select backend is enabled (which is by default)
+  ev_select.c     only when select backend is enabled (which is enabled by default)

   ev_poll.c       only when poll backend is enabled (disabled by default)
   ev_epoll.c      only when the epoll backend is enabled (disabled by default)
   ev_kqueue.c     only when the kqueue backend is enabled (disabled by default)
   ev_poll.c       only when poll backend is enabled (disabled by default)
   ev_epoll.c      only when the epoll backend is enabled (disabled by default)
   ev_kqueue.c     only when the kqueue backend is enabled (disabled by default)


@@ -1845,6 +2049,12 @@ backend for Solaris 10 systems.
 
 reserved for future expansion, works like the USE symbols above.
 
 
 reserved for future expansion, works like the USE symbols above.
 

+=item EV_USE_INOTIFY
+
+If defined to be C<1>, libev will compile in support for the Linux inotify
+interface to speed up C<ev_stat> watchers. Its actual availability will
+be detected at runtime.
+

 =item EV_H
 
 The name of the F<ev.h> header file used to include it. The default if
 =item EV_H
 
 The name of the F<ev.h> header file used to include it. The default if


@@ -1893,12 +2103,32 @@ defined to be C<0>, then they are not.
 If undefined or defined to be C<1>, then stat watchers are supported. If
 defined to be C<0>, then they are not.
 
 If undefined or defined to be C<1>, then stat watchers are supported. If
 defined to be C<0>, then they are not.
 

+=item EV_FORK_ENABLE
+
+If undefined or defined to be C<1>, then fork watchers are supported. If
+defined to be C<0>, then they are not.
+

 =item EV_MINIMAL
 
 If you need to shave off some kilobytes of code at the expense of some
 speed, define this symbol to C<1>. Currently only used for gcc to override
 some inlining decisions, saves roughly 30% codesize of amd64.
 
 =item EV_MINIMAL
 
 If you need to shave off some kilobytes of code at the expense of some
 speed, define this symbol to C<1>. Currently only used for gcc to override
 some inlining decisions, saves roughly 30% codesize of amd64.
 

+=item EV_PID_HASHSIZE
+
+C<ev_child> watchers use a small hash table to distribute workload by
+pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more
+than enough. If you need to manage thousands of children you might want to
+increase this value (I<must> be a power of two).
+
+=item EV_INOTIFY_HASHSIZE
+
+C<ev_staz> watchers use a small hash table to distribute workload by
+inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),
+usually more than enough. If you need to manage thousands of C<ev_stat>
+watchers you might want to increase this value (I<must> be a power of
+two).
+

 =item EV_COMMON
 
 By default, all watchers have a C<void *data> member. By redefining
 =item EV_COMMON
 
 By default, all watchers have a C<void *data> member. By redefining


@@ -1936,12 +2166,17 @@ will be compiled. It is pretty complex because it provides its own header
 file.
 
 The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
 file.
 
 The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file

-that everybody includes and which overrides some autoconf choices:
+that everybody includes and which overrides some configure choices:

 
 

+  #define EV_MINIMAL 1

   #define EV_USE_POLL 0
   #define EV_MULTIPLICITY 0
   #define EV_USE_POLL 0
   #define EV_MULTIPLICITY 0

-  #define EV_PERIODICS 0
+  #define EV_PERIODIC_ENABLE 0
+  #define EV_STAT_ENABLE 0
+  #define EV_FORK_ENABLE 0

   #define EV_CONFIG_H <config.h>
   #define EV_CONFIG_H <config.h>

+  #define EV_MINPRI 0
+  #define EV_MAXPRI 0

 
   #include "ev++.h"
 
 
   #include "ev++.h"
 


@@ -1967,7 +2202,7 @@ documentation for C<ev_default_init>.
 
 =item Stopping check/prepare/idle watchers: O(1)
 
 
 =item Stopping check/prepare/idle watchers: O(1)
 

-=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))
+=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))

 
 =item Finding the next timer per loop iteration: O(1)
 
 
 =item Finding the next timer per loop iteration: O(1)