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<h1 class="title">The EvStat class</h1>
<div class="partintro"><p class="verinfo">(PECL ev >= 0.2.0)</p>
<div class="section" id="evstat.intro">
<h2 class="title">Introduction</h2>
<p class="para">
<strong class="classname">EvStat</strong>
monitors a file system path for attribute changes. It calls
<em class="emphasis">stat()</em>
on that path in regular intervals(or when the OS signals it changed) and
sees if it changed compared to the last time, invoking the callback if it
did.
</p>
<p class="para">
The path does not need to exist: changing from "path exists" to "path does
not exist" is a status change like any other. The condition "path does not
exist" is signified by the
<strong><code>'nlink'</code></strong>
item being 0(returned by
<span class="methodname"><a href="evstat.attr.html" class="methodname">EvStat::attr()</a></span>
method).
</p>
<p class="para">
The path must not end in a slash or contain special components such as
<strong><code>'.'</code></strong>
or
<strong><code>..</code></strong>
. The path should be absolute: if it is relative and the working directory
changes, then the behaviour is undefined.
</p>
<p class="para">
Since there is no portable change notification interface available, the
portable implementation simply calls
<em class="emphasis">stat()</em>
regularly on the path to see if it changed somehow. For this case a
recommended polling interval can be specified. If one specifies a polling
interval of
<strong><code>0.0 </code></strong>
(highly recommended) then a suitable, unspecified default value will be
used(which could be expected to be around 5 seconds, although this might
change dynamically).
<em class="emphasis">libev</em>
will also impose a minimum interval which is currently around
<strong><code>0.1</code></strong>
, but that’s usually overkill.
</p>
<p class="para">
This watcher type is not meant for massive numbers of
<strong class="classname">EvStat</strong>
watchers, as even with OS-supported change notifications, this can be
resource-intensive.
</p>
</div>
<div class="section" id="evstat.synopsis">
<h2 class="title">Class synopsis</h2>
<div class="classsynopsis">
<div class="ooclass">
</div>
<div class="classsynopsisinfo">
<span class="ooclass">
<strong class="classname">EvStat</strong>
</span>
<span class="ooclass">
<span class="modifier">extends</span>
<a href="class.evwatcher.html" class="classname">EvWatcher</a>
</span>
{</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Properties */</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<var class="varname"><a href="class.evstat.html#evstat.props.path">$<var class="varname">path</var></a></var>
;</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<var class="varname"><a href="class.evstat.html#evstat.props.interval">$<var class="varname">interval</var></a></var>
;</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Inherited properties */</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<var class="varname"><a href="class.evwatcher.html#evwatcher.props.is-active">$<var class="varname">is_active</var></a></var>
;</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<var class="varname"><a href="class.evwatcher.html#evwatcher.props.data">$<var class="varname">data</var></a></var>
;</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<var class="varname"><a href="class.evwatcher.html#evwatcher.props.is-pending">$<var class="varname">is_pending</var></a></var>
;</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<var class="varname"><a href="class.evwatcher.html#evwatcher.props.priority">$<var class="varname">priority</var></a></var>
;</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">array</span>
<span class="methodname"><a href="evstat.attr.html" class="methodname">attr</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="methodname"><a href="evstat.construct.html" class="methodname">__construct</a></span>
( <span class="methodparam">
<span class="type">string</span>
<code class="parameter">$path</code>
</span>
, <span class="methodparam">
<span class="type">double</span>
<code class="parameter">$interval</code>
</span>
, <span class="methodparam">
<span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span>
<code class="parameter">$callback</code>
</span>
[, <span class="methodparam">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span>
<code class="parameter">$data</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
[, <span class="methodparam">
<span class="type">int</span>
<code class="parameter">$priority</code>
<span class="initializer"> = 0</span>
</span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">final</span>
<span class="modifier">public</span>
<span class="modifier">static</span>
<span class="type">void</span>
<span class="methodname"><a href="evstat.createstopped.html" class="methodname">createStopped</a></span>
( <span class="methodparam">
<span class="type">string</span>
<code class="parameter">$path</code>
</span>
, <span class="methodparam">
<span class="type">double</span>
<code class="parameter">$interval</code>
</span>
, <span class="methodparam">
<span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span>
<code class="parameter">$callback</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">$data</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
[, <span class="methodparam">
<span class="type">int</span>
<code class="parameter">$priority</code>
<span class="initializer"> = 0</span>
</span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">void</span>
<span class="methodname"><a href="evstat.prev.html" class="methodname">prev</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="evstat.set.html" class="methodname">set</a></span>
( <span class="methodparam">
<span class="type">string</span>
<code class="parameter">$path</code>
</span>
, <span class="methodparam">
<span class="type">double</span>
<code class="parameter">$interval</code>
</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">bool</span>
<span class="methodname"><a href="evstat.stat.html" class="methodname">stat</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Inherited methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">int</span>
<span class="methodname"><a href="evwatcher.clear.html" class="methodname">EvWatcher::clear</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">abstract</span>
<span class="modifier">public</span>
<span class="methodname"><a href="evwatcher.construct.html" class="methodname">EvWatcher::__construct</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="evwatcher.feed.html" class="methodname">EvWatcher::feed</a></span>
( <span class="methodparam">
<span class="type">int</span>
<code class="parameter">$revents</code>
</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">EvLoop</span>
<span class="methodname"><a href="evwatcher.getloop.html" class="methodname">EvWatcher::getLoop</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">void</span>
<span class="methodname"><a href="evwatcher.invoke.html" class="methodname">EvWatcher::invoke</a></span>
( <span class="methodparam">
<span class="type">int</span>
<code class="parameter">$revents</code>
</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">bool</span>
<span class="methodname"><a href="evwatcher.keepalive.html" class="methodname">EvWatcher::keepalive</a></span>
([ <span class="methodparam">
<span class="type">bool</span>
<code class="parameter">$value</code>
</span>
] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">void</span>
<span class="methodname"><a href="evwatcher.setcallback.html" class="methodname">EvWatcher::setCallback</a></span>
( <span class="methodparam">
<span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span>
<code class="parameter">$callback</code>
</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span>
<span class="type">void</span>
<span class="methodname"><a href="evwatcher.start.html" class="methodname">EvWatcher::start</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="evwatcher.stop.html" class="methodname">EvWatcher::stop</a></span>
( <span class="methodparam">void</span>
)</div>
}</div>
</div>
<div class="section" id="evstat.props">
<h2 class="title">Properties</h2>
<dl>
<dt id="evstat.props.interval">
<span class="term">
<var class="varname"><var class="varname">interval</var></var>
</span>
<dd>
<p class="para">
<em class="emphasis">Readonly</em>
. Hint on how quickly a change is expected to be detected and should
normally be specified as
<strong><code>0.0</code></strong>
to let
<em class="emphasis">libev</em>
choose a suitable value.
</p>
</dd>
</dt>
<dt id="evstat.props.path">
<span class="term">
<var class="varname"><var class="varname">path</var></var>
</span>
<dd>
<p class="para">
<em class="emphasis">Readonly</em>
. The path to wait for status changes on.
</p>
</dd>
</dt>
</dl>
</div>
</div>
<h2>Table of Contents</h2><ul class="chunklist chunklist_reference"><li><a href="evstat.attr.html">EvStat::attr</a> — Returns the values most recently detected by Ev</li><li><a href="evstat.construct.html">EvStat::__construct</a> — Constructs EvStat watcher object</li><li><a href="evstat.createstopped.html">EvStat::createStopped</a> — Create a stopped EvStat watcher object</li><li><a href="evstat.prev.html">EvStat::prev</a> — Returns the previous set of values returned by EvStat::attr</li><li><a href="evstat.set.html">EvStat::set</a> — Configures the watcher</li><li><a href="evstat.stat.html">EvStat::stat</a> — Initiates the stat call</li></ul>
</div>
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