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<title>The Volatile class</title>
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<h1 class="title">The Volatile class</h1>
<div class="partintro"><p class="verinfo">(PECL pthreads >= 3.0.0)</p>
<div class="section" id="volatile.intro">
<h2 class="title">Introduction</h2>
<p class="para">
The <strong class="classname">Volatile</strong> class is new to pthreads v3. Its
introduction is a consequence of the new immutability semantics of
<a href="class.threaded.html" class="classname">Threaded</a> members of <a href="class.threaded.html" class="classname">Threaded</a>
classes. The <strong class="classname">Volatile</strong> class enables for mutability
of its <a href="class.threaded.html" class="classname">Threaded</a> members, and is also used to store
PHP arrays in <a href="class.threaded.html" class="classname">Threaded</a> contexts.
</p>
</div>
<div class="section" id="volatile.synopsis">
<h2 class="title">Class synopsis</h2>
<div class="classsynopsis">
<div class="ooclass"></div>
<div class="classsynopsisinfo">
<span class="ooclass">
<strong class="classname">Volatile</strong>
</span>
<span class="ooclass">
<span class="modifier">extends</span>
<a href="class.threaded.html" class="classname">Threaded</a>
</span>
<span class="oointerface">implements
<span class="interfacename"><a href="class.collectable.html" class="interfacename">Collectable</a></span>
</span>
<span class="oointerface">,
<span class="interfacename"><a href="class.traversable.html" class="interfacename">Traversable</a></span>
</span>
{</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Inherited methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><a href="threaded.chunk.html" class="methodname">Threaded::chunk</a></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$size</code></span>
, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$preserve</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">int</span> <span class="methodname"><a href="threaded.count.html" class="methodname">Threaded::count</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.extend.html" class="methodname">Threaded::extend</a></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$class</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">Threaded</span> <span class="methodname"><a href="threaded.from.html" class="methodname">Threaded::from</a></span>
( <span class="methodparam"><span class="type"><a href="class.closure.html" class="type Closure">Closure</a></span> <code class="parameter">$run</code></span>
[, <span class="methodparam"><span class="type"><a href="class.closure.html" class="type Closure">Closure</a></span> <code class="parameter">$construct</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$args</code></span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><a href="threaded.getterminationinfo.html" class="methodname">Threaded::getTerminationInfo</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="thread.isrunning.html" class="methodname">Threaded::isRunning</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.isterminated.html" class="methodname">Threaded::isTerminated</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.iswaiting.html" class="methodname">Threaded::isWaiting</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.lock.html" class="methodname">Threaded::lock</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.merge.html" class="methodname">Threaded::merge</a></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$from</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$overwrite</code></span>
] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.notify.html" class="methodname">Threaded::notify</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.notifyone.html" class="methodname">Threaded::notifyOne</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.pop.html" class="methodname">Threaded::pop</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">void</span> <span class="methodname"><a href="threaded.run.html" class="methodname">Threaded::run</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">mixed</span> <span class="methodname"><a href="threaded.shift.html" class="methodname">Threaded::shift</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">mixed</span> <span class="methodname"><a href="threaded.synchronized.html" class="methodname">Threaded::synchronized</a></span>
( <span class="methodparam"><span class="type"><a href="class.closure.html" class="type Closure">Closure</a></span> <code class="parameter">$block</code></span>
[, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$...</code></span>
] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.unlock.html" class="methodname">Threaded::unlock</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="threaded.wait.html" class="methodname">Threaded::wait</a></span>
([ <span class="methodparam"><span class="type">int</span> <code class="parameter">$timeout</code></span>
] )</div>
}</div>
</div>
<div class="section" id="volatile.examples">
<h2 class="title">Examples</h2>
<div class="example" id="example-4544">
<p><strong>Example #1 New immutability semantics of Threaded</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #007700">class </span><span style="color: #0000BB">Task </span><span style="color: #007700">extends </span><span style="color: #0000BB">Threaded<br /></span><span style="color: #007700">{<br /> public function </span><span style="color: #0000BB">__construct</span><span style="color: #007700">()<br /> {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data </span><span style="color: #007700">= new </span><span style="color: #0000BB">Threaded</span><span style="color: #007700">();<br /><br /> </span><span style="color: #FF8000">// attempt to overwrite a Threaded property of a Threaded class (invalid)<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data </span><span style="color: #007700">= new </span><span style="color: #0000BB">StdClass</span><span style="color: #007700">();<br /> }<br />}<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">((new </span><span style="color: #0000BB">Task</span><span style="color: #007700">())-></span><span style="color: #0000BB">data</span><span style="color: #007700">);</span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output
something similar to:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
RuntimeException: Threaded members previously set to Threaded objects are immutable, cannot overwrite data in %s:%d
</pre></div>
</div>
</div>
<div class="example" id="example-4545">
<p><strong>Example #2 Volatile use-case</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #007700">class </span><span style="color: #0000BB">Task </span><span style="color: #007700">extends </span><span style="color: #0000BB">Volatile<br /></span><span style="color: #007700">{<br /> public function </span><span style="color: #0000BB">__construct</span><span style="color: #007700">()<br /> {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data </span><span style="color: #007700">= new </span><span style="color: #0000BB">Threaded</span><span style="color: #007700">();<br /><br /> </span><span style="color: #FF8000">// attempt to overwrite a Threaded property of a Volatile class (valid)<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data </span><span style="color: #007700">= new </span><span style="color: #0000BB">StdClass</span><span style="color: #007700">();<br /> }<br />}<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">((new </span><span style="color: #0000BB">Task</span><span style="color: #007700">())-></span><span style="color: #0000BB">data</span><span style="color: #007700">);</span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output
something similar to:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
object(stdClass)#3 (0) {
}
</pre></div>
</div>
</div>
</div>
</div>
</div>
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