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
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
-completely useless). For this reason its not being "autodetected"
+anything but sockets and pipes, except on Darwin, where of course it's
+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>).
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
such as poll (fortunately in our Xlib example, Xlib already does this on
its own, so its quite safe to use).
+=head3 The special problem of disappearing file descriptors
+
+Some backends (e.g kqueue, epoll) need to be told about closing a file
+descriptor (either by calling C<close> explicitly or by any other means,
+such as C<dup>). The reason is that you register interest in some file
+descriptor, but when it goes away, the operating system will silently drop
+this interest. If another file descriptor with the same number then is
+registered with libev, there is no efficient way to see that this is, in
+fact, a different file descriptor.
+
+To avoid having to explicitly tell libev about such cases, libev follows
+the following policy: Each time C<ev_io_set> is being called, libev
+will assume that this is potentially a new file descriptor, otherwise
+it is assumed that the file descriptor stays the same. That means that
+you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the
+descriptor even if the file descriptor number itself did not change.
+
+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)
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)
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)
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
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)
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)
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)
"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)
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)
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)
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)
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>.
=head1 MACRO MAGIC
-Libev can be compiled with a variety of options, the most fundemantal is
-C<EV_MULTIPLICITY>. This option determines whether (most) functions and
-callbacks have an initial C<struct ev_loop *> argument.
+Libev can be compiled with a variety of options, the most fundamantal
+of which is C<EV_MULTIPLICITY>. This option determines whether (most)
+functions and callbacks have an initial C<struct ev_loop *> argument.
To make it easier to write programs that cope with either variant, the
following macros are defined:
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
-in the description of C<EV_USE_MONOTONIC>, though.
+(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
+note about libraries in the description of C<EV_USE_MONOTONIC>, though.
=item EV_USE_SELECT
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 comamnd 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
projects / software / libev.git / blobdiff