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

Comparing libev/ev.pod (file contents):
Revision 1.81 by root, Wed Dec 12 04:53:58 2007 UTC vs.
Revision 1.93 by root, Fri Dec 21 01:29:34 2007 UTC

 The newest version of this document is also available as a html-formatted
 web page you might find easier to navigate when reading it for the first
 time: L<http://cvs.schmorp.de/libev/ev.html>.
 Libev is an event loop: you register interest in certain events (such as a
-file descriptor being readable or a timeout occuring), and it will manage
+file descriptor being readable or a timeout occurring), and it will manage
 these event sources and provide your program with events.
 To do this, it must take more or less complete control over your process
 (or thread) by executing the I<event loop> handler, and will then
 communicate events via a callback mechanism.
 Libev represents time as a single floating point number, representing the
 (fractional) number of seconds since the (POSIX) epoch (somewhere near
 the beginning of 1970, details are complicated, don't ask). This type is
 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.
+it, you should treat it as some floatingpoint value. Unlike the name
+component C<stamp> might indicate, it is also used for time differences
+throughout libev.
 =head1 GLOBAL FUNCTIONS
 These functions can be called anytime, even before initialising the
 library in any way.
 =item C<EVBACKEND_KQUEUE>  (value 8, most BSD clones)
 Kqueue deserves special mention, as at the time of this writing, it
 was broken on all BSDs except NetBSD (usually it doesn't work with
-anything but sockets and pipes, except on Darwin, where of course its
+anything but sockets and pipes, except on Darwin, where of course it's
-completely useless). For this reason its not being "autodetected"
+completely useless). For this reason it's not being "autodetected"
 unless you explicitly specify it explicitly in the flags (i.e. using
 C<EVBACKEND_KQUEUE>).
 It scales in the same way as the epoll backend, but the interface to the
 kernel is more efficient (which says nothing about its actual speed, of
 Destroys the default loop again (frees all memory and kernel state
 etc.). None of the active event watchers will be stopped in the normal
 sense, so e.g. C<ev_is_active> might still return true. It is your
 responsibility to either stop all watchers cleanly yoursef I<before>
 calling this function, or cope with the fact afterwards (which is usually
-the easiest thing, youc na just ignore the watchers and/or C<free ()> them
+the easiest thing, you can just ignore the watchers and/or C<free ()> them
 for example).
+Note that certain global state, such as signal state, will not be freed by
+this function, and related watchers (such as signal and child watchers)
+would need to be stopped manually.
+In general it is not advisable to call this function except in the
+rare occasion where you really need to free e.g. the signal handling
+pipe fds. If you need dynamically allocated loops it is better to use
+C<ev_loop_new> and C<ev_loop_destroy>).
 =item ev_loop_destroy (loop)
 Like C<ev_default_destroy>, but destroys an event loop created by an
 earlier call to C<ev_loop_new>.
 Returns the current "event loop time", which is the time the event loop
 received events and started processing them. This timestamp does not
 change as long as callbacks are being processed, and this is also the base
 time used for relative timers. You can treat it as the timestamp of the
-event occuring (or more correctly, libev finding out about it).
+event occurring (or more correctly, libev finding out about it).
 =item ev_loop (loop, int flags)
 Finally, this is it, the event handler. This function usually is called
 after you initialised all your watchers and you want to start handling
 This is how one would do it normally anyway, the important point is that
 the libev application should not optimise around libev but should leave
 optimisations to libev.
+=head3 Watcher-Specific Functions
 =over 4
 =item ev_io_init (ev_io *, callback, int fd, int events)
 =item ev_io_set (ev_io *, int fd, int events)
    ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
 The callback is guarenteed to be invoked only when its timeout has passed,
 but if multiple timers become ready during the same loop iteration then
 order of execution is undefined.
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
 As with timers, the callback is guarenteed to be invoked only when the
 time (C<at>) has been passed, but if multiple periodic timers become ready
 during the same loop iteration then order of execution is undefined.
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)
 =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)
 =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]
 The current reschedule callback, or C<0>, if this functionality is
 switched off. Can be changed any time, but changes only take effect when
 the periodic timer fires or C<ev_periodic_again> is being called.
+=item ev_tstamp at [read-only]
+When active, contains the absolute time that the watcher is supposed to
+trigger next.
 =back
 Example: Call a callback every hour, or, more precisely, whenever the
 system clock is divisible by 3600. The callback invocation times have
 with the kernel (thus it coexists with your own signal handlers as long
 as you don't register any with libev). Similarly, when the last signal
 watcher for a signal is stopped libev will reset the signal handler to
 SIG_DFL (regardless of what it was set to before).
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_signal_init (ev_signal *, callback, int signum)
 =item ev_signal_set (ev_signal *, int signum)
 =head2 C<ev_child> - watch out for process status changes
 Child watchers trigger when your process receives a SIGCHLD in response to
 some child status changes (most typically when a child of yours dies).
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_child_init (ev_child *, callback, int pid)
 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.
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)
 Apart from keeping your process non-blocking (which is a useful
 effect on its own sometimes), idle watchers are a good place to do
 "pseudo-background processing", or delay processing stuff to after the
 event loop has handled all outstanding events.
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_idle_init (ev_signal *, callback)
 Initialises and configures the idle watcher - it has no parameters of any
 their job. As C<ev_check> watchers are often used to embed other event
 loops those other event loops might be in an unusable state until their
 C<ev_check> watcher ran (always remind yourself to coexist peacefully with
 others).
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_prepare_init (ev_prepare *, callback)
 =item ev_check_init (ev_check *, callback)
       ev_embed_start (loop_hi, &embed);
     }
   else
     loop_lo = loop_hi;
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)
 =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)
 Make a single, non-blocking sweep over the embedded loop. This works
 similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
 apropriate way for embedded loops.
-=item struct ev_loop *loop [read-only]
+=item struct ev_loop *other [read-only]
 The embedded event loop.
 =back
 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.
+=head3 Watcher-Specific Functions and Data Members
 =over 4
 =item ev_fork_init (ev_signal *, callback)
 Initialises and configures the fork watcher - it has no parameters of any
 =item w->stop ()
 Stops the watcher if it is active. Again, no C<loop> argument.
-=item w->again ()       C<ev::timer>, C<ev::periodic> only
+=item w->again () (C<ev::timer>, C<ev::periodic> only)
 For C<ev::timer> and C<ev::periodic>, this invokes the corresponding
 C<ev_TYPE_again> function.
-=item w->sweep ()       C<ev::embed> only
+=item w->sweep () (C<ev::embed> only)
 Invokes C<ev_embed_sweep>.
-=item w->update ()      C<ev::stat> only
+=item w->update () (C<ev::stat> only)
 Invokes C<ev_stat_stat>.
 =back
   }
 =head1 MACRO MAGIC
-Libev can be compiled with a variety of options, the most fundemantal is
+Libev can be compiled with a variety of options, the most fundamantal
-C<EV_MULTIPLICITY>. This option determines whether (most) functions and
+of which is C<EV_MULTIPLICITY>. This option determines whether (most)
-callbacks have an initial C<struct ev_loop *> argument.
+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
 Libev can (and often is) directly embedded into host
 applications. Examples of applications that embed it include the Deliantra
 Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
 and rxvt-unicode.
-The goal is to enable you to just copy the neecssary files into your
+The goal is to enable you to just copy the necessary 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).
 =head2 FILESETS
 If defined to be C<1>, 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
+the functionality isn't available is safe, though, although you have
 to make sure you link against any libraries where the C<clock_gettime>
 function is hiding in (often F<-lrt>).
 =item EV_USE_REALTIME
 If defined to be C<1>, 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 C<gettimeofday> by C<clock_get
-(CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries
+(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
-in the description of C<EV_USE_MONOTONIC>, though.
+note about libraries in the description of C<EV_USE_MONOTONIC>, though.
 =item EV_USE_SELECT
 If undefined or defined to be C<1>, libev will compile in support for the
 C<select>(2) backend. No attempt at autodetection will be done: if no
 =item ev_set_cb (ev, cb)
 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 F<ev.v> header file for
+definition and a statement, respectively. See the F<ev.h> header file for
 their default definitions. One possible use for overriding these is to
 avoid the C<struct ev_loop *> as first argument in all cases, or to use
 method calls instead of plain function calls in C++.
+=head2 EXPORTED API SYMBOLS
+If you need to re-export the API (e.g. via a dll) and you need a list of
+exported symbols, you can use the provided F<Symbol.*> files which list
+all public symbols, one per line:
+  Symbols.ev      for libev proper
+  Symbols.event   for the libevent emulation
+This can also be used to rename all public symbols to avoid clashes with
+multiple versions of libev linked together (which is obviously bad in
+itself, but sometimes it is inconvinient to avoid this).
+A sed command like this will create wrapper C<#define>'s that you need to
+include before including F<ev.h>:
+   <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h
+This would create a file F<wrap.h> which essentially looks like this:
+   #define ev_backend     myprefix_ev_backend
+   #define ev_check_start myprefix_ev_check_start
+   #define ev_check_stop  myprefix_ev_check_stop
+   ...
 =head2 EXAMPLES
 For a real-world example of a program the includes libev
 verbatim, you can have a look at the EV perl module

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Comparing libev/ev.pod (file contents): Revision 1.81 by root, Wed Dec 12 04:53:58 2007 UTC vs. Revision 1.93 by root, Fri Dec 21 01:29:34 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.81 by root, Wed Dec 12 04:53:58 2007 UTC vs.
Revision 1.93 by root, Fri Dec 21 01:29:34 2007 UTC