*** empty log message ***

[software/libev.git] / ev.3

diff --git a/ev.3 b/ev.3
index 46ffd2c1e0ffe1a6930830fbc0d49ca65c521da9..01e5c65dd6e6ad60ddf9d41bdc363c41f788530c 100644 (file)
--- a/ev.3
+++ b/ev.3
@@ -129,7 +129,7 @@
 .\" ========================================================================
 .\"
 .IX Title ""<STANDARD INPUT>" 1"
 .\" ========================================================================
 .\"
 .IX Title ""<STANDARD INPUT>" 1"

-.TH "<STANDARD INPUT>" 1 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation"
+.TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation"

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


@@ -686,6 +686,10 @@ The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been receive
 .el .IP "\f(CWEV_CHILD\fR" 4
 .IX Item "EV_CHILD"
 The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change.
 .el .IP "\f(CWEV_CHILD\fR" 4
 .IX Item "EV_CHILD"
 The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change.

+.ie n .IP """EV_STAT""" 4
+.el .IP "\f(CWEV_STAT\fR" 4
+.IX Item "EV_STAT"
+The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow.

 .ie n .IP """EV_IDLE""" 4
 .el .IP "\f(CWEV_IDLE\fR" 4
 .IX Item "EV_IDLE"
 .ie n .IP """EV_IDLE""" 4
 .el .IP "\f(CWEV_IDLE\fR" 4
 .IX Item "EV_IDLE"


@@ -705,6 +709,15 @@ received events. Callbacks of both watcher types can start and stop as
 many watchers as they want, and all of them will be taken into account
 (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep
 \&\f(CW\*(C`ev_loop\*(C'\fR from blocking).
 many watchers as they want, and all of them will be taken into account
 (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep
 \&\f(CW\*(C`ev_loop\*(C'\fR from blocking).

+.ie n .IP """EV_EMBED""" 4
+.el .IP "\f(CWEV_EMBED\fR" 4
+.IX Item "EV_EMBED"
+The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention.
+.ie n .IP """EV_FORK""" 4
+.el .IP "\f(CWEV_FORK\fR" 4
+.IX Item "EV_FORK"
+The event loop has been resumed in the child process after fork (see
+\&\f(CW\*(C`ev_fork\*(C'\fR).

 .ie n .IP """EV_ERROR""" 4
 .el .IP "\f(CWEV_ERROR\fR" 4
 .IX Item "EV_ERROR"
 .ie n .IP """EV_ERROR""" 4
 .el .IP "\f(CWEV_ERROR\fR" 4
 .IX Item "EV_ERROR"


@@ -719,8 +732,8 @@ for example it might indicate that a fd is readable or writable, and if
 your callbacks is well-written it can just attempt the operation and cope
 with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded
 programs, though, so beware.
 your callbacks is well-written it can just attempt the operation and cope
 with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded
 programs, though, so beware.

-.Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"
-.IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS"
+.Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"
+.IX Subsection "GENERIC WATCHER FUNCTIONS"

 In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type,
 e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers.
 .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
 In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type,
 e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers.
 .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4


@@ -736,7 +749,7 @@ which rolls both calls into one.
 You can reinitialise a watcher at any time as long as it has been stopped
 (or never started) and there are no pending events outstanding.
 .Sp
 You can reinitialise a watcher at any time as long as it has been stopped
 (or never started) and there are no pending events outstanding.
 .Sp

-The callbakc is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher,
+The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher,

 int revents)\*(C'\fR.
 .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4
 .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4
 int revents)\*(C'\fR.
 .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4
 .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4


@@ -823,15 +836,27 @@ have been omitted....
 .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

-information given in the last section.
-.ie n .Sh """ev_io"" \- is this file descriptor readable or writable"
-.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable"
-.IX Subsection "ev_io - is this file descriptor readable or writable"
+information given in the last section. Any initialisation/set macros,
+functions and members specific to the watcher type are explained.
+.PP
+Members are additionally marked with either \fI[read\-only]\fR, meaning that,
+while the watcher is active, you can look at the member and expect some
+sensible content, but you must not modify it (you can modify it while the
+watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
+means you can expect it to have some sensible content while the watcher
+is active, but you can also modify it. Modifying it may not do something
+sensible or take immediate effect (or do anything at all), but libev will
+not crash or malfunction in any way.
+.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"
+.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?"
+.IX Subsection "ev_io - is this file descriptor readable or writable?"

 I/O watchers check whether a file descriptor is readable or writable
 I/O watchers check whether a file descriptor is readable or writable

-in each iteration of the event loop (This behaviour is called
-level-triggering because you keep receiving events as long as the
-condition persists. Remember you can stop the watcher if you don't want to
-act on the event and neither want to receive future events).
+in each iteration of the event loop, or, more precisely, when reading
+would not block the process and writing would at least be able to write
+some data. This behaviour is called level-triggering because you keep
+receiving events as long as the condition persists. Remember you can stop
+the watcher if you don't want to act on the event and neither want to
+receive future events.

 .PP
 In general you can register as many read and/or write event watchers per
 fd as you want (as long as you don't confuse yourself). Setting all file
 .PP
 In general you can register as many read and/or write event watchers per
 fd as you want (as long as you don't confuse yourself). Setting all file


@@ -841,32 +866,42 @@ required if you know what you are doing).
 You have to be careful with dup'ed file descriptors, though. Some backends
 (the linux epoll backend is a notable example) cannot handle dup'ed file
 descriptors correctly if you register interest in two or more fds pointing
 You have to be careful with dup'ed file descriptors, though. Some backends
 (the linux epoll backend is a notable example) cannot handle dup'ed file
 descriptors correctly if you register interest in two or more fds pointing

-to the same underlying file/socket etc. description (that is, they share
+to the same underlying file/socket/etc. description (that is, they share

 the same underlying \*(L"file open\*(R").
 .PP
 If you must do this, then force the use of a known-to-be-good backend
 (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and
 \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR).
 the same underlying \*(L"file open\*(R").
 .PP
 If you must do this, then force the use of a known-to-be-good backend
 (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and
 \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR).

+.PP
+Another thing you have to watch out for is that it is quite easy to
+receive \*(L"spurious\*(R" readyness notifications, that is your callback might
+be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block
+because there is no data. Not only are some backends known to create a
+lot of those (for example solaris ports), it is very easy to get into
+this situation even with a relatively standard program structure. Thus
+it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning
+\&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives.
+.PP
+If you cannot run the fd in non-blocking mode (for example you should not
+play around with an Xlib connection), then you have to seperately re-test
+wether a file descriptor is really ready with a known-to-be good interface
+such as poll (fortunately in our Xlib example, Xlib already does this on
+its own, so its quite safe to use).

 .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
 .IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
 .PD 0
 .IP "ev_io_set (ev_io *, int fd, int events)" 4
 .IX Item "ev_io_set (ev_io *, int fd, int events)"
 .PD
 .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
 .IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
 .PD 0
 .IP "ev_io_set (ev_io *, int fd, int events)" 4
 .IX Item "ev_io_set (ev_io *, int fd, int events)"
 .PD

-Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive
-events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_READ |
-EV_WRITE\*(C'\fR to receive the given events.
-.Sp
-Please note that most of the more scalable backend mechanisms (for example
-epoll and solaris ports) can result in spurious readyness notifications
-for file descriptors, so you practically need to use non-blocking I/O (and
-treat callback invocation as hint only), or retest separately with a safe
-interface before doing I/O (XLib can do this), or force the use of either
-\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this
-problem. Also note that it is quite easy to have your callback invoked
-when the readyness condition is no longer valid even when employing
-typical ways of handling events, so its a good idea to use non-blocking
-I/O unconditionally.
+Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to
+rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or
+\&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events.
+.IP "int fd [read\-only]" 4
+.IX Item "int fd [read-only]"
+The file descriptor being watched.
+.IP "int events [read\-only]" 4
+.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
 readable, but only once. Since it is likely line\-buffered, you could
 .PP
 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


@@ -889,9 +924,9 @@ attempt to read a whole line in the callback:
 \&  ev_io_start (loop, &stdin_readable);
 \&  ev_loop (loop, 0);
 .Ve
 \&  ev_io_start (loop, &stdin_readable);
 \&  ev_loop (loop, 0);
 .Ve

-.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts"
-.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts"
-.IX Subsection "ev_timer - relative and optionally recurring timeouts"
+.ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts"
+.el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
+.IX Subsection "ev_timer - relative and optionally repeating timeouts"

 Timer watchers are simple relative timers that generate an event after a
 given time, and optionally repeating in regular intervals after that.
 .PP
 Timer watchers are simple relative timers that generate an event after a
 given time, and optionally repeating in regular intervals after that.
 .PP


@@ -941,13 +976,36 @@ If the timer is repeating, either start it if necessary (with the repeat
 value), or reset the running timer to the repeat value.
 .Sp
 This sounds a bit complicated, but here is a useful and typical
 value), or reset the running timer to the repeat value.
 .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 after=repeat=60 and calling 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.
+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
+\&\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.
+.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:
+.Sp
+.Vb 8
+\&   ev_timer_init (timer, callback, 0., 5.);
+\&   ev_timer_again (loop, timer);
+\&   ...
+\&   timer->again = 17.;
+\&   ev_timer_again (loop, timer);
+\&   ...
+\&   timer->again = 10.;
+\&   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.
+.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.
 .PP
 .PP
 Example: create a timer that fires after 60 seconds.
 .PP


@@ -988,9 +1046,9 @@ inactivity.
 \&  // reset the timeout to start ticking again at 10 seconds
 \&  ev_timer_again (&mytimer);
 .Ve
 \&  // reset the timeout to start ticking again at 10 seconds
 \&  ev_timer_again (&mytimer);
 .Ve

-.ie n .Sh """ev_periodic"" \- to cron or not to cron"
-.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron"
-.IX Subsection "ev_periodic - to cron or not to cron"
+.ie n .Sh """ev_periodic"" \- to cron or not to cron?"
+.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?"
+.IX Subsection "ev_periodic - to cron or not to cron?"

 Periodic watchers are also timers of a kind, but they are very versatile
 (and unfortunately a bit complex).
 .PP
 Periodic watchers are also timers of a kind, but they are very versatile
 (and unfortunately a bit complex).
 .PP


@@ -1089,6 +1147,16 @@ Simply stops and restarts the periodic watcher again. This is only useful
 when you changed some parameters or the reschedule callback would return
 a different time than the last time it was called (e.g. in a crond like
 program when the crontabs have changed).
 when you changed some parameters or the reschedule callback would return
 a different time than the last time it was called (e.g. in a crond like
 program when the crontabs have changed).

+.IP "ev_tstamp interval [read\-write]" 4
+.IX Item "ev_tstamp interval [read-write]"
+The current interval value. Can be modified any time, but changes only
+take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being
+called.
+.IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4
+.IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]"
+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
 Example: call a callback every hour, or, more precisely, whenever the
 system clock is divisible by 3600. The callback invocation times have
 .PP
 Example: call a callback every hour, or, more precisely, whenever the
 system clock is divisible by 3600. The callback invocation times have


@@ -1134,9 +1202,9 @@ Example: call a callback every hour, starting now:
 \&                    fmod (ev_now (loop), 3600.), 3600., 0);
 \&  ev_periodic_start (loop, &hourly_tick);
 .Ve
 \&                    fmod (ev_now (loop), 3600.), 3600., 0);
 \&  ev_periodic_start (loop, &hourly_tick);
 .Ve

-.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled"
-.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled"
-.IX Subsection "ev_signal - signal me when a signal gets signalled"
+.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!"
+.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!"
+.IX Subsection "ev_signal - signal me when a signal gets signalled!"

 Signal watchers will trigger an event when the process receives a specific
 signal one or more times. Even though signals are very asynchronous, libev
 will try it's best to deliver signals synchronously, i.e. as part of the
 Signal watchers will trigger an event when the process receives a specific
 signal one or more times. Even though signals are very asynchronous, libev
 will try it's best to deliver signals synchronously, i.e. as part of the


@@ -1156,9 +1224,12 @@ watcher for a signal is stopped libev will reset the signal handler to
 .PD
 Configures the watcher to trigger on the given signal number (usually one
 of the \f(CW\*(C`SIGxxx\*(C'\fR constants).
 .PD
 Configures the watcher to trigger on the given signal number (usually one
 of the \f(CW\*(C`SIGxxx\*(C'\fR constants).

-.ie n .Sh """ev_child"" \- wait for pid status changes"
-.el .Sh "\f(CWev_child\fP \- wait for pid status changes"
-.IX Subsection "ev_child - wait for pid status changes"
+.IP "int signum [read\-only]" 4
+.IX Item "int signum [read-only]"
+The signal the watcher watches out for.
+.ie n .Sh """ev_child"" \- watch out for process status changes"
+.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
+.IX Subsection "ev_child - watch out for process status changes"

 Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
 some child status changes (most typically when a child of yours dies).
 .IP "ev_child_init (ev_child *, callback, int pid)" 4
 Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
 some child status changes (most typically when a child of yours dies).
 .IP "ev_child_init (ev_child *, callback, int pid)" 4


@@ -1173,6 +1244,16 @@ at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watche
 the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems
 \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the
 process causing the status change.
 the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems
 \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the
 process causing the status change.

+.IP "int pid [read\-only]" 4
+.IX Item "int pid [read-only]"
+The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
+.IP "int rpid [read\-write]" 4
+.IX Item "int rpid [read-write]"
+The process id that detected a status change.
+.IP "int rstatus [read\-write]" 4
+.IX Item "int rstatus [read-write]"
+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.
 .PP
 .PP
 Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
 .PP


@@ -1189,9 +1270,104 @@ Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
 \&  ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
 \&  ev_signal_start (loop, &sigint_cb);
 .Ve
 \&  ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
 \&  ev_signal_start (loop, &sigint_cb);
 .Ve

-.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_stat"" \- did the file attributes just change?"
+.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
+.IX Subsection "ev_stat - did the file attributes just change?"
+This watches a filesystem path for attribute changes. That is, it calls
+\&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
+compared to the last time, invoking the callback if it did.
+.PP
+The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does
+not exist\*(R" is a status change like any other. The condition \*(L"path does
+not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR 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.
+.PP
+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
+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
+five seconds, although this might change dynamically). Libev will also
+impose a minimum interval which is currently around \f(CW0.1\fR, but thats
+usually overkill.
+.PP
+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
+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.
+.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_set (ev_stat *, const char *path, ev_tstamp interval)" 4
+.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)"
+.PD
+Configures the watcher to wait for status changes of the given
+\&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to
+be detected and should normally be specified as \f(CW0\fR to let libev choose
+a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same
+path for as long as the watcher is active.
+.Sp
+The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected,
+relative to the attributes at the time the watcher was started (or the
+last change was detected).
+.IP "ev_stat_stat (ev_stat *)" 4
+.IX Item "ev_stat_stat (ev_stat *)"
+Updates the stat buffer immediately with new values. If you change the
+watched path in your callback, you could call this fucntion to avoid
+detecting this change (while introducing a race condition). Can also be
+useful simply to find out the new values.
+.IP "ev_statdata attr [read\-only]" 4
+.IX Item "ev_statdata attr [read-only]"
+The most-recently detected attributes of the file. Although the type is of
+\&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types
+suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there
+was some error while \f(CW\*(C`stat\*(C'\fRing the file.
+.IP "ev_statdata prev [read\-only]" 4
+.IX Item "ev_statdata prev [read-only]"
+The previous attributes of the file. The callback gets invoked whenever
+\&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR.
+.IP "ev_tstamp interval [read\-only]" 4
+.IX Item "ev_tstamp interval [read-only]"
+The specified interval.
+.IP "const char *path [read\-only]" 4
+.IX Item "const char *path [read-only]"
+The filesystem path that is being watched.
+.PP
+Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes.
+.PP
+.Vb 15
+\&  static void
+\&  passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
+\&  {
+\&    /* /etc/passwd changed in some way */
+\&    if (w->attr.st_nlink)
+\&      {
+\&        printf ("passwd current size  %ld\en", (long)w->attr.st_size);
+\&        printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
+\&        printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
+\&      }
+\&    else
+\&      /* you shalt not abuse printf for puts */
+\&      puts ("wow, /etc/passwd is not there, expect problems. "
+\&            "if this is windows, they already arrived\en");
+\&  }
+.Ve
+.PP
+.Vb 2
+\&  ...
+\&  ev_stat passwd;
+.Ve
+.PP
+.Vb 2
+\&  ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
+\&  ev_stat_start (loop, &passwd);
+.Ve
+.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,
 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,


@@ -1231,17 +1407,28 @@ callback, free it. Alos, use no error checking, as usual.
 \&  ev_idle_init (idle_watcher, idle_cb);
 \&  ev_idle_start (loop, idle_cb);
 .Ve
 \&  ev_idle_init (idle_watcher, idle_cb);
 \&  ev_idle_start (loop, idle_cb);
 .Ve

-.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop"
-.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop"
-.IX Subsection "ev_prepare and ev_check - customise your event loop"
+.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!"
+.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
+.IX Subsection "ev_prepare and ev_check - customise your event loop!"

 Prepare and check watchers are usually (but not always) used in tandem:
 prepare watchers get invoked before the process blocks and check watchers
 afterwards.
 .PP
 Prepare and check watchers are usually (but not always) used in tandem:
 prepare watchers get invoked before the process blocks and check watchers
 afterwards.
 .PP

+You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter
+the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR
+watchers. Other loops than the current one are fine, however. The
+rationale behind this is that you do not need to check for recursion in
+those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking,
+\&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be
+called in pairs bracketing the blocking call.
+.PP

 Their main purpose is to integrate other event mechanisms into libev and
 their use is somewhat advanced. This could be used, for example, to track
 variable changes, implement your own watchers, integrate net-snmp or a
 Their main purpose is to integrate other event mechanisms into libev and
 their use is somewhat advanced. This could be used, for example, to track
 variable changes, implement your own watchers, integrate net-snmp or a

-coroutine library and lots more.
+coroutine library and lots more. They are also occasionally useful if
+you cache some data and want to flush it before blocking (for example,
+in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR
+watcher).

 .PP
 This is done by examining in each prepare call which file descriptors need
 to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for
 .PP
 This is done by examining in each prepare call which file descriptors need
 to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for


@@ -1270,10 +1457,81 @@ Initialises and configures the prepare or check watcher \- they have no
 parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR
 macros, but using them is utterly, utterly and completely pointless.
 .PP
 parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR
 macros, but using them is utterly, utterly and completely pointless.
 .PP

-Example: *TODO*.
-.ie n .Sh """ev_embed"" \- when one backend isn't enough"
-.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough"
-.IX Subsection "ev_embed - when one backend isn't enough"
+Example: To include a library such as adns, you would add \s-1IO\s0 watchers
+and a timeout watcher in a prepare handler, as required by libadns, and
+in a check watcher, destroy them and call into libadns. What follows is
+pseudo-code only of course:
+.PP
+.Vb 2
+\&  static ev_io iow [nfd];
+\&  static ev_timer tw;
+.Ve
+.PP
+.Vb 9
+\&  static void
+\&  io_cb (ev_loop *loop, ev_io *w, int revents)
+\&  {
+\&    // set the relevant poll flags
+\&    // could also call adns_processreadable etc. here
+\&    struct pollfd *fd = (struct pollfd *)w->data;
+\&    if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
+\&    if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
+\&  }
+.Ve
+.PP
+.Vb 7
+\&  // 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];
+\&    // actual code will need to loop here and realloc etc.
+\&    adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
+.Ve
+.PP
+.Vb 3
+\&    /* the callback is illegal, but won't be called as we stop during check */
+\&    ev_timer_init (&tw, 0, timeout * 1e-3);
+\&    ev_timer_start (loop, &tw);
+.Ve
+.PP
+.Vb 6
+\&    // create on ev_io per pollfd
+\&    for (int i = 0; i < nfd; ++i)
+\&      {
+\&        ev_io_init (iow + i, io_cb, fds [i].fd,
+\&          ((fds [i].events & POLLIN ? EV_READ : 0)
+\&           | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
+.Ve
+.PP
+.Vb 5
+\&        fds [i].revents = 0;
+\&        iow [i].data = fds + i;
+\&        ev_io_start (loop, iow + i);
+\&      }
+\&  }
+.Ve
+.PP
+.Vb 5
+\&  // stop all watchers after blocking
+\&  static void
+\&  adns_check_cb (ev_loop *loop, ev_check *w, int revents)
+\&  {
+\&    ev_timer_stop (loop, &tw);
+.Ve
+.PP
+.Vb 2
+\&    for (int i = 0; i < nfd; ++i)
+\&      ev_io_stop (loop, iow + i);
+.Ve
+.PP
+.Vb 2
+\&    adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
+\&  }
+.Ve
+.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
+.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
+.IX Subsection "ev_embed - when one backend isn't enough..."

 This is a rather advanced watcher type that lets you embed one event loop
 into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded
 loop, other types of watchers might be handled in a delayed or incorrect
 This is a rather advanced watcher type that lets you embed one event loop
 into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded
 loop, other types of watchers might be handled in a delayed or incorrect


@@ -1363,6 +1621,24 @@ if you do not want thta, you need to temporarily stop the embed watcher).
 Make a single, non-blocking sweep over the embedded loop. This works
 similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most
 apropriate way for embedded loops.
 Make a single, non-blocking sweep over the embedded loop. This works
 similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most
 apropriate way for embedded loops.

+.IP "struct ev_loop *loop [read\-only]" 4
+.IX Item "struct ev_loop *loop [read-only]"
+The embedded event loop.
+.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
+.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
+.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
+Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because
+whoever is a good citizen cared to tell libev about it by calling
+\&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the
+event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called,
+and only in the child after the fork. If whoever good citizen calling
+\&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork
+handlers will be invoked, too, of course.
+.IP "ev_fork_init (ev_signal *, callback)" 4
+.IX Item "ev_fork_init (ev_signal *, callback)"
+Initialises and configures the fork watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless,
+believe me.

 .SH "OTHER FUNCTIONS"
 .IX Header "OTHER FUNCTIONS"
 There are some other functions of possible interest. Described. Here. Now.
 .SH "OTHER FUNCTIONS"
 .IX Header "OTHER FUNCTIONS"
 There are some other functions of possible interest. Described. Here. Now.


@@ -1511,6 +1787,10 @@ For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes
 .el .IP "w\->sweep ()       \f(CWev::embed\fR only" 4
 .IX Item "w->sweep ()       ev::embed only"
 Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR.
 .el .IP "w\->sweep ()       \f(CWev::embed\fR only" 4
 .IX Item "w->sweep ()       ev::embed only"
 Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR.

+.ie n .IP "w\->update ()      ""ev::stat"" only" 4
+.el .IP "w\->update ()      \f(CWev::stat\fR only" 4
+.IX Item "w->update ()      ev::stat only"
+Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR.

 .RE
 .RS 4
 .RE
 .RE
 .RS 4
 .RE


@@ -1538,6 +1818,392 @@ the constructor.
 \&    io.start (fd, ev::READ);
 \&  }
 .Ve
 \&    io.start (fd, ev::READ);
 \&  }
 .Ve

+.SH "MACRO MAGIC"
+.IX Header "MACRO MAGIC"
+Libev can be compiled with a variety of options, the most fundemantal is
+\&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and
+callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument.
+.PP
+To make it easier to write programs that cope with either variant, the
+following macros are defined:
+.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
+.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
+.IX Item "EV_A, EV_A_"
+This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
+loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument,
+\&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example:
+.Sp
+.Vb 3
+\&  ev_unref (EV_A);
+\&  ev_timer_add (EV_A_ watcher);
+\&  ev_loop (EV_A_ 0);
+.Ve
+.Sp
+It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope,
+which is often provided by the following macro.
+.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
+.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
+.IX Item "EV_P, EV_P_"
+This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
+loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter,
+\&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example:
+.Sp
+.Vb 2
+\&  // this is how ev_unref is being declared
+\&  static void ev_unref (EV_P);
+.Ve
+.Sp
+.Vb 2
+\&  // this is how you can declare your typical callback
+\&  static void cb (EV_P_ ev_timer *w, int revents)
+.Ve
+.Sp
+It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite
+suitable for use with \f(CW\*(C`EV_A\*(C'\fR.
+.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
+.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
+.IX Item "EV_DEFAULT, EV_DEFAULT_"
+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.
+.PP
+.Vb 5
+\&  static void
+\&  check_cb (EV_P_ ev_timer *w, int revents)
+\&  {
+\&    ev_check_stop (EV_A_ w);
+\&  }
+.Ve
+.PP
+.Vb 4
+\&  ev_check check;
+\&  ev_check_init (&check, check_cb);
+\&  ev_check_start (EV_DEFAULT_ &check);
+\&  ev_loop (EV_DEFAULT_ 0);
+.Ve
+.SH "EMBEDDING"
+.IX Header "EMBEDDING"
+Libev can (and often is) directly embedded into host
+applications. Examples of applications that embed it include the Deliantra
+Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe)
+and rxvt\-unicode.
+.PP
+The goal is to enable you to just copy the neecssary files into your
+source directory without having to change even a single line in them, so
+you can easily upgrade by simply copying (or having a checked-out copy of
+libev somewhere in your source tree).
+.Sh "\s-1FILESETS\s0"
+.IX Subsection "FILESETS"
+Depending on what features you need you need to include one or more sets of files
+in your app.
+.PP
+\fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR
+.IX Subsection "CORE EVENT LOOP"
+.PP
+To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual
+configuration (no autoconf):
+.PP
+.Vb 2
+\&  #define EV_STANDALONE 1
+\&  #include "ev.c"
+.Ve
+.PP
+This will automatically include \fIev.h\fR, too, and should be done in a
+single C source file only to provide the function implementations. To use
+it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best
+done by writing a wrapper around \fIev.h\fR that you can include instead and
+where you can put other configuration options):
+.PP
+.Vb 2
+\&  #define EV_STANDALONE 1
+\&  #include "ev.h"
+.Ve
+.PP
+Both header files and implementation files can be compiled with a \*(C+
+compiler (at least, thats a stated goal, and breakage will be treated
+as a bug).
+.PP
+You need the following files in your source tree, or in a directory
+in your include path (e.g. in libev/ when using \-Ilibev):
+.PP
+.Vb 4
+\&  ev.h
+\&  ev.c
+\&  ev_vars.h
+\&  ev_wrap.h
+.Ve
+.PP
+.Vb 1
+\&  ev_win32.c      required on win32 platforms only
+.Ve
+.PP
+.Vb 5
+\&  ev_select.c     only when select backend is enabled (which is 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_port.c       only when the solaris port backend is enabled (disabled by default)
+.Ve
+.PP
+\&\fIev.c\fR includes the backend files directly when enabled, so you only need
+to compile this single file.
+.PP
+\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
+.IX Subsection "LIBEVENT COMPATIBILITY API"
+.PP
+To include the libevent compatibility \s-1API\s0, also include:
+.PP
+.Vb 1
+\&  #include "event.c"
+.Ve
+.PP
+in the file including \fIev.c\fR, and:
+.PP
+.Vb 1
+\&  #include "event.h"
+.Ve
+.PP
+in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR.
+.PP
+You need the following additional files for this:
+.PP
+.Vb 2
+\&  event.h
+\&  event.c
+.Ve
+.PP
+\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
+.IX Subsection "AUTOCONF SUPPORT"
+.PP
+Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in
+whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your
+\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then
+include \fIconfig.h\fR and configure itself accordingly.
+.PP
+For this of course you need the m4 file:
+.PP
+.Vb 1
+\&  libev.m4
+.Ve
+.Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0"
+.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
+Libev can be configured via a variety of preprocessor symbols you have to define
+before including any of its files. The default is not to build for multiplicity
+and only include the select backend.
+.IP "\s-1EV_STANDALONE\s0" 4
+.IX Item "EV_STANDALONE"
+Must always be \f(CW1\fR if you do not use autoconf configuration, which
+keeps libev from including \fIconfig.h\fR, and it also defines dummy
+implementations for some libevent functions (such as logging, which is not
+supported). It will also not define any of the structs usually found in
+\&\fIevent.h\fR that are not directly supported by the libev core alone.
+.IP "\s-1EV_USE_MONOTONIC\s0" 4
+.IX Item "EV_USE_MONOTONIC"
+If defined to be \f(CW1\fR, libev will try to detect the availability of the
+monotonic clock option at both compiletime 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, althoguh you have
+to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR
+function is hiding in (often \fI\-lrt\fR).
+.IP "\s-1EV_USE_REALTIME\s0" 4
+.IX Item "EV_USE_REALTIME"
+If defined to be \f(CW1\fR, libev will try to detect the availability of the
+realtime clock option at compiletime (and assume its availability at
+runtime if successful). Otherwise no use of the realtime clock option will
+be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get
+(CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries
+in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though.
+.IP "\s-1EV_USE_SELECT\s0" 4
+.IX Item "EV_USE_SELECT"
+If undefined or defined to be \f(CW1\fR, libev will compile in support for the
+\&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no
+other method takes over, select will be it. Otherwise the select backend
+will not be compiled in.
+.IP "\s-1EV_SELECT_USE_FD_SET\s0" 4
+.IX Item "EV_SELECT_USE_FD_SET"
+If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR
+structure. This is useful if libev doesn't compile due to a missing
+\&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses 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 \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might
+influence the size of the \f(CW\*(C`fd_set\*(C'\fR used.
+.IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4
+.IX Item "EV_SELECT_IS_WINSOCKET"
+When defined to \f(CW1\fR, the select backend will assume that
+select/socket/connect etc. don't understand file descriptors but
+wants osf handles on win32 (this is the case when the select to
+be used is the winsock select). This means that it will call
+\&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise,
+it is assumed that all these functions actually work on fds, even
+on win32. Should not be defined on non\-win32 platforms.
+.IP "\s-1EV_USE_POLL\s0" 4
+.IX Item "EV_USE_POLL"
+If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2)
+backend. Otherwise it will be enabled on non\-win32 platforms. It
+takes precedence over select.
+.IP "\s-1EV_USE_EPOLL\s0" 4
+.IX Item "EV_USE_EPOLL"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux
+\&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the
+preferred backend for GNU/Linux systems.
+.IP "\s-1EV_USE_KQUEUE\s0" 4
+.IX Item "EV_USE_KQUEUE"
+If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style
+\&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
+supports some types of fds correctly (the only platform we found that
+supports ptys for example was NetBSD), so kqueue might be compiled in, but
+not be used unless explicitly requested. The best way to use it is to find
+out whether kqueue supports your type of fd properly and use an embedded
+kqueue loop.
+.IP "\s-1EV_USE_PORT\s0" 4
+.IX Item "EV_USE_PORT"
+If defined to be \f(CW1\fR, libev will compile in support for the Solaris
+10 port style backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+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_H\s0" 4
+.IX Item "EV_H"
+The name of the \fIev.h\fR header file used to include it. The default if
+undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
+can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
+.IP "\s-1EV_CONFIG_H\s0" 4
+.IX Item "EV_CONFIG_H"
+If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override
+\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
+\&\f(CW\*(C`EV_H\*(C'\fR, above.
+.IP "\s-1EV_EVENT_H\s0" 4
+.IX Item "EV_EVENT_H"
+Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea
+of how the \fIevent.h\fR header can be found.
+.IP "\s-1EV_PROTOTYPES\s0" 4
+.IX Item "EV_PROTOTYPES"
+If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
+prototypes, but still define all the structs and other symbols. This is
+occasionally useful if you want to provide your own wrapper functions
+around libev functions.
+.IP "\s-1EV_MULTIPLICITY\s0" 4
+.IX Item "EV_MULTIPLICITY"
+If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
+will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create
+additional independent event loops. Otherwise there will be no support
+for multiple event loops and there is no first event loop pointer
+argument. Instead, all functions act on the single default loop.
+.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
+.IX Item "EV_PERIODIC_ENABLE"
+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_EMBED_ENABLE\s0" 4
+.IX Item "EV_EMBED_ENABLE"
+If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
+defined to be \f(CW0\fR, then they are not.
+.IP "\s-1EV_STAT_ENABLE\s0" 4
+.IX Item "EV_STAT_ENABLE"
+If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
+defined to be \f(CW0\fR, then they are not.
+.IP "\s-1EV_FORK_ENABLE\s0" 4
+.IX Item "EV_FORK_ENABLE"
+If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
+defined to be \f(CW0\fR, then they are not.
+.IP "\s-1EV_MINIMAL\s0" 4
+.IX Item "EV_MINIMAL"
+If you need to shave off some kilobytes of code at the expense of some
+speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
+some inlining decisions, saves roughly 30% codesize of amd64.
+.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
+this macro to a something else you can include more and other types of
+members. You have to define it each time you include one of the files,
+though, and it must be identical each time.
+.Sp
+For example, the perl \s-1EV\s0 module uses something like this:
+.Sp
+.Vb 3
+\&  #define EV_COMMON                       \e
+\&    SV *self; /* contains this struct */  \e
+\&    SV *cb_sv, *fh /* note no trailing ";" */
+.Ve
+.IP "\s-1EV_CB_DECLARE\s0 (type)" 4
+.IX Item "EV_CB_DECLARE (type)"
+.PD 0
+.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4
+.IX Item "EV_CB_INVOKE (watcher, revents)"
+.IP "ev_set_cb (ev, cb)" 4
+.IX Item "ev_set_cb (ev, cb)"
+.PD
+Can be used to change the callback member declaration in each watcher,
+and the way callbacks are invoked and set. Must expand to a struct member
+definition and a statement, respectively. See the \fIev.v\fR header file for
+their default definitions. One possible use for overriding these is to
+avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use
+method calls instead of plain function calls in \*(C+.
+.Sh "\s-1EXAMPLES\s0"
+.IX Subsection "EXAMPLES"
+For a real-world example of a program the includes libev
+verbatim, you can have a look at the \s-1EV\s0 perl module
+(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
+the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public
+interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
+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
+that everybody includes and which overrides some autoconf choices:
+.Sp
+.Vb 4
+\&  #define EV_USE_POLL 0
+\&  #define EV_MULTIPLICITY 0
+\&  #define EV_PERIODICS 0
+\&  #define EV_CONFIG_H <config.h>
+.Ve
+.Sp
+.Vb 1
+\&  #include "ev++.h"
+.Ve
+.Sp
+And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
+.Sp
+.Vb 2
+\&  #include "ev_cpp.h"
+\&  #include "ev.c"
+.Ve
+.SH "COMPLEXITIES"
+.IX Header "COMPLEXITIES"
+In this section the complexities of (many of) the algorithms used inside
+libev will be explained. For complexity discussions about backends see the
+documentation for \f(CW\*(C`ev_default_init\*(C'\fR.
+.RS 4
+.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
+.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
+.PD 0
+.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
+.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
+.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
+.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 "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
+.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
+.IP "Activating one watcher: O(1)" 4
+.IX Item "Activating one watcher: O(1)"
+.RE
+.RS 4
+.PD

 .SH "AUTHOR"
 .IX Header "AUTHOR"
 Marc Lehmann <libev@schmorp.de>.
 .SH "AUTHOR"
 .IX Header "AUTHOR"
 Marc Lehmann <libev@schmorp.de>.