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</div><hr /><div id="intro.eio" class="preface">
<h1 class="title">Introduction</h1>
<p class="para">
This extension provides asyncronous POSIX I/O by means of <a href="http://software.schmorp.de/pkg/libeio.html" class="link external">» libeio</a> C
library written by Marc Lehmann.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">This extension is not
available on Windows platforms.</span></p></blockquote>
<p class="para">
<div class="warning"><strong class="warning">Warning</strong>
<p class="simpara">
It is important to aware that each request is executed in a thread, and the
order of execution of continuously queued requests basically is
unpredictable. For instance, the following piece of code is incorrect.
</p>
</div>
<div class="example" id="example-3578">
<p><strong>Example #1 Incorrect requests</strong></p>
<div class="example-contents"><div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Request to create symlink of $filename to $link<br /></span><span style="color: #0000BB">eio_symlink</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #0000BB">$link</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Request to move $filename to $new_filename<br /></span><span style="color: #0000BB">eio_rename</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #0000BB">$new_filename</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Process requests<br /></span><span style="color: #0000BB">eio_event_loop</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
In the example above <span class="function"><a href="function.eio-rename.html" class="function">eio_rename()</a></span> request may finish
before <span class="function"><a href="function.eio-symlink.html" class="function">eio_symlink()</a></span>. To fix it you might call <span class="function"><a href="function.eio-rename.html" class="function">eio_rename()</a></span>
in the callback of <span class="function"><a href="function.eio-symlink.html" class="function">eio_symlink()</a></span>:
<div class="example" id="example-3579">
<p><strong>Example #2 Calling request from a request callback</strong></p>
<div class="example-contents"><div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">my_symlink_done</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #0000BB">$result</span><span style="color: #007700">) {<br /> </span><span style="color: #FF8000">// Request to move $filename to $new_filename<br /> </span><span style="color: #0000BB">eio_rename</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #DD0000">"/path/to/new-name"</span><span style="color: #007700">);<br /><br /> </span><span style="color: #FF8000">// Process requests<br /> </span><span style="color: #0000BB">eio_event_loop</span><span style="color: #007700">();<br />}<br /><br /></span><span style="color: #FF8000">// Request to create symlink of $filename to $link<br /></span><span style="color: #0000BB">eio_symlink</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #0000BB">$link</span><span style="color: #007700">, </span><span style="color: #0000BB">EIO_PRI_DEFAULT</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_symlink_done"</span><span style="color: #007700">, </span><span style="color: #0000BB">$filename</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Process requests<br /></span><span style="color: #0000BB">eio_event_loop</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
Alternatively, you might want to create a request group:
<div class="example" id="example-3580">
<p><strong>Example #3 Calling request from a request callback</strong></p>
<div class="example-contents"><div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/* Is called when the group requests are done */<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">my_grp_done</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">, </span><span style="color: #0000BB">$result</span><span style="color: #007700">) {<br /> </span><span style="color: #FF8000">// ...<br /></span><span style="color: #007700">}<br /><br />function </span><span style="color: #0000BB">my_symlink_done</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #0000BB">$result</span><span style="color: #007700">) {<br /> </span><span style="color: #FF8000">// Create eio_rename request and add it to the group<br /> </span><span style="color: #0000BB">$req </span><span style="color: #007700">= </span><span style="color: #0000BB">eio_rename</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #DD0000">"/path/to/new-name"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">eio_grp_add</span><span style="color: #007700">(</span><span style="color: #0000BB">$grp</span><span style="color: #007700">, </span><span style="color: #0000BB">$req</span><span style="color: #007700">);<br /> </span><span style="color: #FF8000">// You might want to add more requests...<br /></span><span style="color: #007700">}<br /><br /></span><span style="color: #FF8000">// Create a request group<br /></span><span style="color: #0000BB">$grp </span><span style="color: #007700">= </span><span style="color: #0000BB">eio_grp</span><span style="color: #007700">(</span><span style="color: #DD0000">"my_grp_done"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_grp_data"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Create eio_symlink request and add it to the group<br />// Pass $filename to the callback<br /></span><span style="color: #0000BB">$req </span><span style="color: #007700">= </span><span style="color: #0000BB">eio_symlink</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, </span><span style="color: #0000BB">$link</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">EIO_PRI_DEFAULT</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_symlink_done"</span><span style="color: #007700">, </span><span style="color: #0000BB">$filename</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">eio_grp_add</span><span style="color: #007700">(</span><span style="color: #0000BB">$grp</span><span style="color: #007700">, </span><span style="color: #0000BB">$req</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Process requests<br /></span><span style="color: #0000BB">eio_event_loop</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div></div>
</div>
Group is a special kind of request that could accumulate a set of regular
<em class="emphasis">eio</em> requests. This could be used to create a complex
request that opens, reads and closes a file.
</p>
<p class="para">
Since version 0.3.0 alpha, a variable used in communications with libeio
internally, could be retrieved with
<span class="function"><a href="function.eio-get-event-stream.html" class="function">eio_get_event_stream()</a></span>. The variable could be used
to bind to an event loop supported by some other extension. You might
organize a simple event loop where eio and libevent work together:
<div class="example" id="example-3581">
<p><strong>Example #4 Using eio with libevent</strong></p>
<div class="example-contents"><div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">my_eio_poll</span><span style="color: #007700">(</span><span style="color: #0000BB">$fd</span><span style="color: #007700">, </span><span style="color: #0000BB">$events</span><span style="color: #007700">, </span><span style="color: #0000BB">$arg</span><span style="color: #007700">) {<br /> </span><span style="color: #FF8000">/* Some libevent regulation might go here .. */<br /> </span><span style="color: #007700">if (</span><span style="color: #0000BB">eio_nreqs</span><span style="color: #007700">()) {<br /> </span><span style="color: #0000BB">eio_poll</span><span style="color: #007700">();<br /> }<br /> </span><span style="color: #FF8000">/* .. and here */<br /></span><span style="color: #007700">}<br /><br />function </span><span style="color: #0000BB">my_res_cb</span><span style="color: #007700">(</span><span style="color: #0000BB">$d</span><span style="color: #007700">, </span><span style="color: #0000BB">$r</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$r</span><span style="color: #007700">); </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$d</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">$base </span><span style="color: #007700">= </span><span style="color: #0000BB">event_base_new</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$event </span><span style="color: #007700">= </span><span style="color: #0000BB">event_new</span><span style="color: #007700">();<br /><br /></span><span style="color: #FF8000">// This stream is used to bind with libevent<br /></span><span style="color: #0000BB">$fd </span><span style="color: #007700">= </span><span style="color: #0000BB">eio_get_event_stream</span><span style="color: #007700">();<br /><br /></span><span style="color: #0000BB">eio_nop</span><span style="color: #007700">(</span><span style="color: #0000BB">EIO_PRI_DEFAULT</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_res_cb"</span><span style="color: #007700">, </span><span style="color: #DD0000">"nop data"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">eio_mkdir</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/abc-eio-temp"</span><span style="color: #007700">, </span><span style="color: #0000BB">0750</span><span style="color: #007700">, </span><span style="color: #0000BB">EIO_PRI_DEFAULT</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_res_cb"</span><span style="color: #007700">, </span><span style="color: #DD0000">"mkdir data"</span><span style="color: #007700">);<br /></span><span style="color: #FF8000">/* some other eio_* calls here ... */<br /><br /><br />// set event flags<br /></span><span style="color: #0000BB">event_set</span><span style="color: #007700">(</span><span style="color: #0000BB">$event</span><span style="color: #007700">, </span><span style="color: #0000BB">$fd</span><span style="color: #007700">, </span><span style="color: #0000BB">EV_READ </span><span style="color: #FF8000">/*| EV_PERSIST*/</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_eio_poll"</span><span style="color: #007700">, array(</span><span style="color: #0000BB">$event</span><span style="color: #007700">, </span><span style="color: #0000BB">$base</span><span style="color: #007700">));<br /><br /></span><span style="color: #FF8000">// set event base <br /></span><span style="color: #0000BB">event_base_set</span><span style="color: #007700">(</span><span style="color: #0000BB">$event</span><span style="color: #007700">, </span><span style="color: #0000BB">$base</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// enable event<br /></span><span style="color: #0000BB">event_add</span><span style="color: #007700">(</span><span style="color: #0000BB">$event</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// start event loop<br /></span><span style="color: #0000BB">event_base_loop</span><span style="color: #007700">(</span><span style="color: #0000BB">$base</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* The same will be available via buffered libevent interface */<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div></div>
</div>
</p>
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