*** empty log message ***

[software/libev.git] / ev.3

diff --git a/ev.3 b/ev.3
index 6c36997c8f6933d9fe531e2b85f2aca4e47c7227..850de71d4635e9bad9c81bc7ea0b3dffb37436ae 100644 (file)
--- a/ev.3
+++ b/ev.3
@@ -129,18 +129,21 @@
 .\" ========================================================================
 .\"
 .IX Title ""<STANDARD INPUT>" 1"
 .\" ========================================================================
 .\"
 .IX Title ""<STANDARD INPUT>" 1"

-.TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation"
+.TH "<STANDARD INPUT>" 1 "2007-12-07" "perl v5.8.8" "User Contributed Perl Documentation"

 .SH "NAME"
 libev \- a high performance full\-featured event loop written in C
 .SH "SYNOPSIS"
 .IX Header "SYNOPSIS"
 .SH "NAME"
 libev \- a high performance full\-featured event loop written in C
 .SH "SYNOPSIS"
 .IX Header "SYNOPSIS"

-.Vb 2
-\&  /* this is the only header you need */
+.Vb 1
+\&  #include <ev.h>
+.Ve
+.SH "EXAMPLE PROGRAM"
+.IX Header "EXAMPLE PROGRAM"
+.Vb 1

 \&  #include <ev.h>
 .Ve
 .PP
 \&  #include <ev.h>
 .Ve
 .PP

-.Vb 3
-\&  /* what follows is a fully working example program */
+.Vb 2

 \&  ev_io stdin_watcher;
 \&  ev_timer timeout_watcher;
 .Ve
 \&  ev_io stdin_watcher;
 \&  ev_timer timeout_watcher;
 .Ve


@@ -209,22 +212,28 @@ details of the event, and then hand it over to libev by \fIstarting\fR the
 watcher.
 .SH "FEATURES"
 .IX Header "FEATURES"
 watcher.
 .SH "FEATURES"
 .IX Header "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 \s-1SIGCHLD\s0), and event watchers dealing with the event
-loop mechanism itself (idle, prepare and check watchers). It also is quite
-fast (see this benchmark comparing
-it to libevent for example).
+Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the
+BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms
+for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface
+(for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers
+with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals
+(\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event
+watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR,
+\&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as
+file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events
+(\f(CW\*(C`ev_fork\*(C'\fR).
+.PP
+It also is quite fast (see this
+benchmark comparing it to libevent
+for example).

 .SH "CONVENTIONS"
 .IX Header "CONVENTIONS"
 .SH "CONVENTIONS"
 .IX Header "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
-\&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without
-support for multiple event loops, then all functions taking an initial
-argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR)
-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 \fB\s-1EMBED\s0\fR section in
+this manual. If libev was configured without support for multiple event
+loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR
+(which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument.

 .SH "TIME REPRESENTATION"
 .IX Header "TIME REPRESENTATION"
 Libev represents time as a single floating point number, representing the
 .SH "TIME REPRESENTATION"
 .IX Header "TIME REPRESENTATION"
 Libev represents time as a single floating point number, representing the


@@ -259,8 +268,8 @@ 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.
 .Sp
 compatible to older versions, so a larger minor version alone is usually
 not a problem.
 .Sp

-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.

 .Sp
 .Vb 3
 \&  assert (("libev version mismatch",
 .Sp
 .Vb 3
 \&  assert (("libev version mismatch",


@@ -298,20 +307,21 @@ might be supported on the current system, you would need to look at
 recommended ones.
 .Sp
 See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
 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, size_t size))" 4
-.IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))"
-Sets the allocation function to use (the prototype and semantics are
-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.
+.IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4
+.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))"
+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.

 .Sp
 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.
 .Sp
 .Sp
 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.
 .Sp

-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).

 .Sp
 .Vb 6
 \&   static void *
 .Sp
 .Vb 6
 \&   static void *


@@ -347,7 +357,7 @@ 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).
 .Sp
 requested operation, or, if the condition doesn't go away, do bad stuff
 (such as abort).
 .Sp

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

 .Sp
 .Vb 6
 \&   static void
 .Sp
 .Vb 6
 \&   static void


@@ -403,6 +413,26 @@ or setgid) then libev will \fInot\fR look at the environment variable
 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.
 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.

+.ie n .IP """EVFLAG_FORKCHECK""" 4
+.el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4
+.IX Item "EVFLAG_FORKCHECK"
+Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \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
+This works by calling \f(CW\*(C`getpid ()\*(C'\fR 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, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence
+without a syscall and thus \fIvery\fR fast, but my Linux system also has
+\&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster).
+.Sp
+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.
+.Sp
+This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR
+environment variable.

 .ie n .IP """EVBACKEND_SELECT""  (value 1, portable select backend)" 4
 .el .IP "\f(CWEVBACKEND_SELECT\fR  (value 1, portable select backend)" 4
 .IX Item "EVBACKEND_SELECT  (value 1, portable select backend)"
 .ie n .IP """EVBACKEND_SELECT""  (value 1, portable select backend)" 4
 .el .IP "\f(CWEVBACKEND_SELECT\fR  (value 1, portable select backend)" 4
 .IX Item "EVBACKEND_SELECT  (value 1, portable select backend)"


@@ -506,7 +536,7 @@ 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).
 .Sp
 handle signal and child watchers, and attempts to do so will be greeted by
 undefined behaviour (or a failed assertion if assertions are enabled).
 .Sp

-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.

 .Sp
 .Vb 3
 \&  struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
 .Sp
 .Vb 3
 \&  struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);


@@ -553,6 +583,15 @@ do not need to care.
 Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by
 \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop
 after fork, and how you do this is entirely your own problem.
 Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by
 \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop
 after fork, and how you do this is entirely your own problem.

+.IP "unsigned int ev_loop_count (loop)" 4
+.IX Item "unsigned int ev_loop_count (loop)"
+Returns the count of loop iterations for the loop, which is identical to
+the number of times libev did poll for new events. It starts at \f(CW0\fR and
+happily wraps around with enough iterations.
+.Sp
+This value can sometimes be useful as a generation counter of sorts (it
+\&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with
+\&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls.

 .IP "unsigned int ev_backend (loop)" 4
 .IX Item "unsigned int ev_backend (loop)"
 Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in
 .IP "unsigned int ev_backend (loop)" 4
 .IX Item "unsigned int ev_backend (loop)"
 Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in


@@ -614,7 +653,7 @@ Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does:
 \&     were used, return, otherwise continue with step *.
 .Ve
 .Sp
 \&     were used, return, otherwise continue with step *.
 .Ve
 .Sp

-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.
 .Sp
 .Vb 4
 anymore.
 .Sp
 .Vb 4


@@ -646,21 +685,21 @@ 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 \fIunref after start\fR and \fIref before stop\fR.
 .Sp
 way to do this for generic recurring timers or from within third-party
 libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
 .Sp

-Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR
+Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR

 running when nothing else is active.
 .Sp
 .Vb 4
 running when nothing else is active.
 .Sp
 .Vb 4

-\&  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);

 .Ve
 .Sp
 .Ve
 .Sp

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

 .Sp
 .Vb 2
 .Sp
 .Vb 2

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

 .Ve
 .SH "ANATOMY OF A WATCHER"
 .IX Header "ANATOMY OF A WATCHER"
 .Ve
 .SH "ANATOMY OF A WATCHER"
 .IX Header "ANATOMY OF A WATCHER"


@@ -850,13 +889,39 @@ events but its callback has not yet been invoked). As long as a watcher
 is pending (but not active) you must not call an init function on it (but
 \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to
 libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it).
 is pending (but not active) you must not call an init function on it (but
 \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to
 libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it).

-.IP "callback = ev_cb (ev_TYPE *watcher)" 4
-.IX Item "callback = ev_cb (ev_TYPE *watcher)"
+.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
 .IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
 Change the callback. You can change the callback at virtually any time
 (modulo threads).
 Returns the callback currently set on the watcher.
 .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
 .IX Item "ev_cb_set (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, priority)" 4
+.IX Item "ev_set_priority (ev_TYPE *watcher, priority)"
+.PD 0
+.IP "int ev_priority (ev_TYPE *watcher)" 4
+.IX Item "int ev_priority (ev_TYPE *watcher)"
+.PD
+Set and query the priority of the watcher. The priority is a small
+integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR
+(default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked
+before watchers with lower priority, but priority will not keep watchers
+from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers).
+.Sp
+This means that priorities are \fIonly\fR used for ordering callback
+invocation after new events have been received. This is useful, for
+example, to reduce latency after idling, or more often, to bind two
+watchers on the same event and make sure one is called first.
+.Sp
+If you need to suppress invocation when higher priority events are pending
+you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality.
+.Sp
+The default priority used by watchers when no priority has been set is
+always \f(CW0\fR, which is supposed to not be too high and not be too low :).
+.Sp
+Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR 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.

 .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"
 .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
 Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change
 .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"
 .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
 Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change


@@ -887,8 +952,45 @@ can cast it back to your own type:
 \&  }
 .Ve
 .PP
 \&  }
 .Ve
 .PP

-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.
+.PP
+Another common scenario is having some data structure with multiple
+watchers:
+.PP
+.Vb 6
+\&  struct my_biggy
+\&  {
+\&    int some_data;
+\&    ev_timer t1;
+\&    ev_timer t2;
+\&  }
+.Ve
+.PP
+In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated,
+you need to use \f(CW\*(C`offsetof\*(C'\fR:
+.PP
+.Vb 1
+\&  #include <stddef.h>
+.Ve
+.PP
+.Vb 6
+\&  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));
+\&  }
+.Ve
+.PP
+.Vb 6
+\&  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));
+\&  }
+.Ve

 .SH "WATCHER TYPES"
 .IX Header "WATCHER TYPES"
 This section describes each watcher in detail, but will not repeat
 .SH "WATCHER TYPES"
 .IX Header "WATCHER TYPES"
 This section describes each watcher in detail, but will not repeat


@@ -959,9 +1061,9 @@ The file descriptor being watched.
 .IX Item "int events [read-only]"
 The events being watched.
 .PP
 .IX Item "int events [read-only]"
 The events being watched.
 .PP

-Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
+Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 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.

 .PP
 .Vb 6
 \&  static void
 .PP
 .Vb 6
 \&  static void


@@ -1026,23 +1128,25 @@ 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:
 .Sp
 This will act as if the timer timed out and restart it again if it is
 repeating. The exact semantics are:
 .Sp

-If the timer is started but nonrepeating, stop it.
+If the timer is pending, its pending status is cleared.
+.Sp
+If the timer is started but nonrepeating, stop it (as if it timed out).

 .Sp
 .Sp

-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 repeating, either start it if necessary (with the
+\&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value.

 .Sp
 This sounds a bit complicated, but here is a useful and typical
 .Sp
 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 \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR 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 \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call

 \&\f(CW\*(C`ev_timer_again\*(C'\fR 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
 \&\f(CW\*(C`ev_timer_again\*(C'\fR 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 \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will
+automatically restart it if need be.

 .Sp
 .Sp

-You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether
-and only ever use the \f(CW\*(C`repeat\*(C'\fR value:
+That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR
+altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR:

 .Sp
 .Vb 8
 \&   ev_timer_init (timer, callback, 0., 5.);
 .Sp
 .Vb 8
 \&   ev_timer_init (timer, callback, 0., 5.);


@@ -1055,15 +1159,15 @@ and only ever use the \f(CW\*(C`repeat\*(C'\fR value:
 \&   ev_timer_again (loop, timer);
 .Ve
 .Sp
 \&   ev_timer_again (loop, timer);
 .Ve
 .Sp

-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.

 .IP "ev_tstamp repeat [read\-write]" 4
 .IX Item "ev_tstamp repeat [read-write]"
 The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out
 or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any),
 which is also when any modifications are taken into account.
 .PP
 .IP "ev_tstamp repeat [read\-write]" 4
 .IX Item "ev_tstamp repeat [read-write]"
 The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out
 or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any),
 which is also when any modifications are taken into account.
 .PP

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

 .PP
 .Vb 5
 \&  static void
 .PP
 .Vb 5
 \&  static void


@@ -1079,7 +1183,7 @@ Example: create a timer that fires after 60 seconds.
 \&  ev_timer_start (loop, &mytimer);
 .Ve
 .PP
 \&  ev_timer_start (loop, &mytimer);
 .Ve
 .PP

-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.
 .PP
 .Vb 5
 inactivity.
 .PP
 .Vb 5


@@ -1214,7 +1318,7 @@ The current reschedule callback, or \f(CW0\fR, if this functionality is
 switched off. Can be changed any time, but changes only take effect when
 the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
 .PP
 switched off. Can be changed any time, but changes only take effect when
 the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
 .PP

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


@@ -1232,7 +1336,7 @@ potentially a lot of jittering, but good long-term stability.
 \&  ev_periodic_start (loop, &hourly_tick);
 .Ve
 .PP
 \&  ev_periodic_start (loop, &hourly_tick);
 .Ve
 .PP

-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:

 .PP
 .Vb 1
 \&  #include <math.h>
 .PP
 .Vb 1
 \&  #include <math.h>


@@ -1250,7 +1354,7 @@ 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);
 .Ve
 .PP
 \&  ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
 .Ve
 .PP

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

 .PP
 .Vb 4
 \&  struct ev_periodic hourly_tick;
 .PP
 .Vb 4
 \&  struct ev_periodic hourly_tick;


@@ -1311,7 +1415,7 @@ The process id that detected a status change.
 The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems
 \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details).
 .PP
 The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems
 \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details).
 .PP

-Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
+Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.

 .PP
 .Vb 5
 \&  static void
 .PP
 .Vb 5
 \&  static void


@@ -1339,8 +1443,11 @@ not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (
 otherwise always forced to be at least one) and all the other fields of
 the stat buffer having unspecified contents.
 .PP
 otherwise always forced to be at least one) and all the other fields of
 the stat buffer having unspecified contents.
 .PP

+The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is
+relative and your working directory changes, the behaviour is undefined.
+.PP

 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 \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You
+calls \f(CW\*(C`stat (2)\*(C'\fR 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 \f(CW0\fR (highly recommended!) then a \fIsuitable,
 unspecified default\fR 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 \f(CW0\fR (highly recommended!) then a \fIsuitable,
 unspecified default\fR value will be used (which you can expect to be around


@@ -1352,8 +1459,13 @@ This watcher type is not meant for massive numbers of stat watchers,
 as even with OS-supported change notifications, this can be
 resource\-intensive.
 .PP
 as even with OS-supported change notifications, this can be
 resource\-intensive.
 .PP

-At the time of this writing, no specific \s-1OS\s0 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 \f(CW\*(C`ev_stat\*(C'\fR 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.

 .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
 .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
 .PD 0
 .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
 .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
 .PD 0


@@ -1424,13 +1536,16 @@ Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes.
 .ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
 .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
 .IX Subsection "ev_idle - when you've got nothing better to do..."
 .ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
 .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
 .IX Subsection "ev_idle - when you've got nothing better to do..."

-Idle watchers trigger events when there are no other events are pending
-(prepare, check and other idle watchers do not count). That is, as long
-as your process is busy handling sockets or timeouts (or even signals,
-imagine) it will not be triggered. But when your process is idle all idle
-watchers are being called again and again, once per event loop iteration \-
-until stopped, that is, or your process receives more events and becomes
-busy.
+Idle watchers trigger events when no other events of the same or higher
+priority are pending (prepare, check and other idle watchers do not
+count).
+.PP
+That is, as long as your process is busy handling sockets or timeouts
+(or even signals, imagine) of the same or higher priority it will not be
+triggered. But when your process is idle (or only lower-priority watchers
+are pending), the idle watchers are being called once per event loop
+iteration \- until stopped, that is, or your process receives more events
+and becomes busy again with higher priority stuff.

 .PP
 The most noteworthy effect is that as long as any idle watchers are
 active, the process will not block when waiting for new events.
 .PP
 The most noteworthy effect is that as long as any idle watchers are
 active, the process will not block when waiting for new events.


@@ -1445,8 +1560,8 @@ Initialises and configures the idle watcher \- it has no parameters of any
 kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
 believe me.
 .PP
 kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
 believe me.
 .PP

-Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the
-callback, free it. Alos, use no error checking, as usual.
+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
 \&  static void
 .PP
 .Vb 7
 \&  static void


@@ -1535,12 +1650,13 @@ pseudo-code only of course:
 \&  }
 .Ve
 .PP
 \&  }
 .Ve
 .PP

-.Vb 7
+.Vb 8

 \&  // create io watchers for each fd and a timer before blocking
 \&  static void
 \&  adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)
 \&  {
 \&  // create io watchers for each fd and a timer before blocking
 \&  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 ()));
 .Ve
 \&    // actual code will need to loop here and realloc etc.
 \&    adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
 .Ve


@@ -1922,8 +2038,9 @@ suitable for use with \f(CW\*(C`EV_A\*(C'\fR.
 Similar to the other two macros, this gives you the value of the default
 loop, if multiple loops are supported (\*(L"ev loop default\*(R").
 .PP
 Similar to the other two macros, this gives you the value of the default
 loop, if multiple loops are supported (\*(L"ev loop default\*(R").
 .PP

-Example: Declare and initialise a check watcher, working regardless of
-wether multiple loops are supported or not.
+Example: Declare and initialise a check watcher, utilising the above
+macros so it will work regardless of wether multiple loops are supported
+or not.

 .PP
 .Vb 5
 \&  static void
 .PP
 .Vb 5
 \&  static void


@@ -1996,7 +2113,7 @@ in your include path (e.g. in libev/ when using \-Ilibev):
 .Ve
 .PP
 .Vb 5
 .Ve
 .PP
 .Vb 5

-\&  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)


@@ -2127,6 +2244,11 @@ backend for Solaris 10 systems.
 .IP "\s-1EV_USE_DEVPOLL\s0" 4
 .IX Item "EV_USE_DEVPOLL"
 reserved for future expansion, works like the \s-1USE\s0 symbols above.
 .IP "\s-1EV_USE_DEVPOLL\s0" 4
 .IX Item "EV_USE_DEVPOLL"
 reserved for future expansion, works like the \s-1USE\s0 symbols above.

+.IP "\s-1EV_USE_INOTIFY\s0" 4
+.IX Item "EV_USE_INOTIFY"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
+interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will
+be detected at runtime.

 .IP "\s-1EV_H\s0" 4
 .IX Item "EV_H"
 The name of the \fIev.h\fR header file used to include it. The default if
 .IP "\s-1EV_H\s0" 4
 .IX Item "EV_H"
 The name of the \fIev.h\fR header file used to include it. The default if


@@ -2159,6 +2281,11 @@ argument. Instead, all functions act on the single default loop.
 If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
 defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
 code.
 If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
 defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
 code.

+.IP "\s-1EV_IDLE_ENABLE\s0" 4
+.IX Item "EV_IDLE_ENABLE"
+If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If
+defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
+code.

 .IP "\s-1EV_EMBED_ENABLE\s0" 4
 .IX Item "EV_EMBED_ENABLE"
 If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
 .IP "\s-1EV_EMBED_ENABLE\s0" 4
 .IX Item "EV_EMBED_ENABLE"
 If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If


@@ -2181,7 +2308,14 @@ some inlining decisions, saves roughly 30% codesize of amd64.
 \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
 pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more
 than enough. If you need to manage thousands of children you might want to
 \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
 pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more
 than enough. If you need to manage thousands of children you might want to

-increase this value.
+increase this value (\fImust\fR be a power of two).
+.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
+.IX Item "EV_INOTIFY_HASHSIZE"
+\&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by
+inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR),
+usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR
+watchers you might want to increase this value (\fImust\fR be a power of
+two).

 .IP "\s-1EV_COMMON\s0" 4
 .IX Item "EV_COMMON"
 By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
 .IP "\s-1EV_COMMON\s0" 4
 .IX Item "EV_COMMON"
 By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining


@@ -2221,13 +2355,18 @@ will be compiled. It is pretty complex because it provides its own header
 file.
 .Sp
 The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
 file.
 .Sp
 The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file

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

 .Sp
 .Sp

-.Vb 4
+.Vb 9
+\&  #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

 .Ve
 .Sp
 .Vb 1
 .Ve
 .Sp
 .Vb 1


@@ -2255,8 +2394,8 @@ documentation for \f(CW\*(C`ev_default_init\*(C'\fR.
 .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
 .IP "Stopping check/prepare/idle watchers: O(1)" 4
 .IX Item "Stopping check/prepare/idle watchers: O(1)"
 .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
 .IP "Stopping check/prepare/idle watchers: O(1)" 4
 .IX Item "Stopping check/prepare/idle watchers: O(1)"

-.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4
-.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))"
+.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
+.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"

 .IP "Finding the next timer per loop iteration: O(1)" 4
 .IX Item "Finding the next timer per loop iteration: O(1)"
 .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
 .IP "Finding the next timer per loop iteration: O(1)" 4
 .IX Item "Finding the next timer per loop iteration: O(1)"
 .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4