<meta name="description" content="Pod documentation for libev" />
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- <meta name="created" content="Mon Nov 12 09:46:41 2007" />
+ <meta name="created" content="Mon Nov 12 10:06:08 2007" />
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<body>
<li><a href="#DESCRIPTION">DESCRIPTION</a></li>
<li><a href="#FEATURES">FEATURES</a></li>
<li><a href="#CONVENTIONS">CONVENTIONS</a></li>
-<li><a href="#TIME_AND_OTHER_GLOBAL_FUNCTIONS">TIME AND OTHER GLOBAL FUNCTIONS</a></li>
+<li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li>
+<li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li>
<li><a href="#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</a></li>
<li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a>
<ul><li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</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_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</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="#prepare_and_check_your_hooks_into_th">prepare and check - your hooks into the event loop</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>
</ul>
</li>
<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>
+<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>
+<li><a href="#C_SUPPORT">C++ SUPPORT</a></li>
<li><a href="#AUTHOR">AUTHOR</a>
</li>
</ul><hr />
will not have this argument.</p>
</div>
-<h1 id="TIME_
AND_OTHER_GLOBAL_FUNCTIONS">TIME AND OTHER GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p>
-<div id="TIME_AND_OTHER_GLOBAL_FUNCTIONS_CONT">
+<h1 id="TIME_
REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p>
+<div id="TIME_REPRESENTATION_CONTENT">
<p>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 <code>ev_tstamp</code>, which is what you should use too. It usually aliases
to the double type in C.</p>
+
+</div>
+<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p>
+<div id="GLOBAL_FUNCTIONS_CONTENT">
+<p>These functions can be called anytime, even before initialising the
+library in any way.</p>
<dl>
<dt>ev_tstamp ev_time ()</dt>
<dd>
types of such loops, the <i>default</i> loop, which supports signals and child
events, and dynamically created loops which do not.</p>
<p>If you use threads, a common model is to run the default event loop
-in your main thread (or in a separate thrad) and for each thread you
+in your main thread (or in a separate thread) and for each thread you
create, you also create another event loop. Libev itself does no locking
whatsoever, so if you mix calls to the same event loop in different
threads, make sure you lock (this is usually a bad idea, though, even if
ignored. Instead, each time the periodic watcher gets scheduled, the
reschedule callback will be called with the watcher as first, and the
current time as second argument.</p>
- <p>NOTE: <i>This callback MUST NOT stop or destroy the periodic or any other
-periodic watcher, ever, or make any event loop modifications</i>. If you need
-to stop it, return <code>now + 1e30</code> (or so, fudge fudge) and stop it afterwards.</p>
- <p>Also, <i>this callback must always return a time that is later than the
-passed <code>now</code> value</i>. Not even <code>now</code> itself will be ok.</p>
+ <p>NOTE: <i>This callback MUST NOT stop or destroy any periodic watcher,
+ever, or make any event loop modifications</i>. If you need to stop it,
+return <code>now + 1e30</code> (or so, fudge fudge) and stop it afterwards (e.g. by
+starting a prepare watcher).</p>
<p>Its prototype is <code>ev_tstamp (*reschedule_cb)(struct ev_periodic *w,
ev_tstamp now)</code>, e.g.:</p>
<pre> static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)
(that is, the lowest time value larger than to the second argument). It
will usually be called just before the callback will be triggered, but
might be called at other times, too.</p>
+ <p>NOTE: <i>This callback must always return a time that is later than the
+passed <code>now</code> value</i>. Not even <code>now</code> itself will do, it <i>must</i> be larger.</p>
<p>This can be used to create very complex timers, such as a timer that
triggers on each midnight, local time. To do this, you would calculate the
-next midnight after <code>now</code> and return the timestamp value for this. How you do this
-is, again, up to you (but it is not trivial).</p>
+next midnight after <code>now</code> and return the timestamp value for this. How
+you do this is, again, up to you (but it is not trivial, which is the main
+reason I omitted it as an example).</p>
</dd>
</dl>
</p>
</dl>
</div>
-<h2 id="prepare_and_check_your_hooks_into_th">prepare and check - your hooks into the event loop</h2>
-<div id="prepare_and_check_your_hooks_into_th-2">
+<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2>
+<div id="code_ev_prepare_code_and_code_ev_che-2">
<p>Prepare and check watchers are usually (but not always) used in tandem:
-Prepare watchers get invoked before the process blocks and check watchers
+prepare watchers get invoked before the process blocks and check watchers
afterwards.</p>
<p>Their main purpose is to integrate other event mechanisms into libev. This
could be used, for example, to track variable changes, implement your own
provide just this functionality). Then, in the check watcher you check for
any events that occured (by checking the pending status of all watchers
and stopping them) and call back into the library. The I/O and timer
-callbacks will never actually be called (but must be valid neverthelles,
+callbacks will never actually be called (but must be valid nevertheless,
because you never know, you know?).</p>
<p>As another example, the Perl Coro module uses these hooks to integrate
coroutines into libev programs, by yielding to other active coroutines
during each prepare and only letting the process block if no coroutines
-are ready to run (its actually more complicated, it only runs coroutines
-with priority higher than the event loop and one lower priority once,
-using idle watchers to keep the event loop from blocking if lower-priority
-coroutines exist, thus mapping low-priority coroutines to idle/background
-tasks).</p>
+are ready to run (it's actually more complicated: it only runs coroutines
+with priority higher than or equal to the event loop and one coroutine
+of lower priority, but only once, using idle watchers to keep the event
+loop from blocking if lower-priority coroutines are active, thus mapping
+low-priority coroutines to idle/background tasks).</p>
<dl>
<dt>ev_prepare_init (ev_prepare *, callback)</dt>
<dt>ev_check_init (ev_check *, callback)</dt>
</dd>
</dl>
+</div>
+<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p>
+<div id="LIBEVENT_EMULATION_CONTENT">
+<p>TBD.</p>
+
+</div>
+<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p>
+<div id="C_SUPPORT_CONTENT">
+<p>TBD.</p>
+
</div>
<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p>
<div id="AUTHOR_CONTENT">
projects / software / libev.git / blobdiff