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- <meta name="created" content="Sun Dec 9 20:45:16 2007" />
+ <meta name="created" content="Wed Dec 12 18:55:04 2007" />
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</ul>
</li>
<li><a href="#WATCHER_TYPES">WATCHER TYPES</a>
-<ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a></li>
-<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li>
-<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a></li>
-<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li>
-<li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a></li>
-<li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</a></li>
-<li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</a></li>
-<li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</a></li>
-<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li>
+<ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a>
+<ul><li><a href="#The_special_problem_of_disappearing_">The special problem of disappearing file descriptors</a></li>
+<li><a href="#Watcher_Specific_Functions">Watcher-Specific Functions</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_-3">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_-4">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_-5">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_-6">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_-7">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_-8">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
+<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a>
+<ul><li><a href="#Watcher_Specific_Functions_and_Data_-9">Watcher-Specific Functions and Data Members</a></li>
+</ul>
+</li>
<li><a href="#code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</a></li>
</ul>
</li>
<dt>int ev_version_major ()</dt>
<dt>int ev_version_minor ()</dt>
<dd>
- <p>You can find out the major and minor API/ABI version numbers of the library
+ <p>You can find out the major and minor ABI version numbers of the library
you linked against by calling the functions <code>ev_version_major</code> and
<code>ev_version_minor</code>. If you want, you can compare against the global
symbols <code>EV_VERSION_MAJOR</code> and <code>EV_VERSION_MINOR</code>, which specify the
version of the library your program was compiled against.</p>
- <p>These version numbers refer to the API and ABI version of the library, not
-the release version.</p>
+ <p>These version numbers refer to the ABI version of the library, not the
+release version.</p>
<p>Usually, it's a good idea to terminate if the major versions mismatch,
as this indicates an incompatible change. Minor versions are usually
compatible to older versions, so a larger minor version alone is usually
whether 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).</p>
+
+</div>
+<h3 id="The_special_problem_of_disappearing_">The special problem of disappearing file descriptors</h3>
+<div id="The_special_problem_of_disappearing_-2">
+<p>Some backends (e.g kqueue, epoll) need to be told about closing a file
+descriptor (either by calling <code>close</code> explicitly or by any other means,
+such as <code>dup</code>). 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.</p>
+<p>To avoid having to explicitly tell libev about such cases, libev follows
+the following policy: Each time <code>ev_io_set</code> 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</i> to call <code>ev_io_set</code> (or <code>ev_io_init</code>) when you change the
+descriptor even if the file descriptor number itself did not change.</p>
+<p>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.</p>
+
+
+
+
+
+</div>
+<h3 id="Watcher_Specific_Functions">Watcher-Specific Functions</h3>
+<div id="Watcher_Specific_Functions_CONTENT">
<dl>
<dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>
<dt>ev_io_set (ev_io *, int fd, int events)</dt>
<p>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.</p>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2">
<dl>
<dt>ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)</dt>
<dt>ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)</dt>
<p>As with timers, the callback is guarenteed to be invoked only when the
time (<code>at</code>) has been passed, but if multiple periodic timers become ready
during the same loop iteration then order of execution is undefined.</p>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_-3">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2">
<dl>
<dt>ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)</dt>
<dt>ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)</dt>
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).</p>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_-4">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2-2">
<dl>
<dt>ev_signal_init (ev_signal *, callback, int signum)</dt>
<dt>ev_signal_set (ev_signal *, int signum)</dt>
<div id="code_ev_child_code_watch_out_for_pro-2">
<p>Child watchers trigger when your process receives a SIGCHLD in response to
some child status changes (most typically when a child of yours dies).</p>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_-5">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2-3">
<dl>
<dt>ev_child_init (ev_child *, callback, int pid)</dt>
<dt>ev_child_set (ev_child *, int pid)</dt>
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.</p>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_-6">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2-4">
<dl>
<dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt>
<dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt>
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.</p>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_-7">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2-5">
<dl>
<dt>ev_idle_init (ev_signal *, callback)</dt>
<dd>
loops those other event loops might be in an unusable state until their
<code>ev_check</code> watcher ran (always remind yourself to coexist peacefully with
others).</p>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_-8">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2-6">
<dl>
<dt>ev_prepare_init (ev_prepare *, callback)</dt>
<dt>ev_check_init (ev_check *, callback)</dt>
loop_lo = loop_hi;
</pre>
+
+</div>
+<h3 id="Watcher_Specific_Functions_and_Data_-9">Watcher-Specific Functions and Data Members</h3>
+<div id="Watcher_Specific_Functions_and_Data_-2-7">
<dl>
<dt>ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)</dt>
<dt>ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)</dt>
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