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<title>Copy data from named shared memory</title>
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<h1 class="refname">SyncSharedMemory::read</h1>
<p class="verinfo">(PECL sync >= 1.1.0)</p><p class="refpurpose"><span class="refname">SyncSharedMemory::read</span> — <span class="dc-title">Copy data from named shared memory</span></p>
</div>
<div class="refsect1 description" id="refsect1-syncsharedmemory.read-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="methodname"><strong>SyncSharedMemory::read</strong></span>
([ <span class="methodparam"><span class="type">int</span> <code class="parameter">$start</code><span class="initializer"> = 0</span></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$length</code></span>
]] )</div>
<p class="para rdfs-comment">
Copies data from named shared memory.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-syncsharedmemory.read-parameters">
<h3 class="title">Parameters</h3>
<dl>
<dt>
<code class="parameter">start</code></dt>
<dd>
<p class="para">
The start/offset, in bytes, to begin reading.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
If the value is negative, the starting position will begin at the specified
number of bytes from the end of the shared memory segment.
</p>
</p></blockquote>
</dd>
<dt>
<code class="parameter">length</code></dt>
<dd>
<p class="para">
The number of bytes to read.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
If unspecified, reading will stop at the end of the shared memory segment.
</p>
<p class="para">
If the value is negative, reading will stop the specified number of bytes
from the end of the shared memory segment.
</p>
</p></blockquote>
</dd>
</dl>
</div>
<div class="refsect1 returnvalues" id="refsect1-syncsharedmemory.read-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
A string containing the data read from shared memory.
</p>
</div>
<div class="refsect1 examples" id="refsect1-syncsharedmemory.read-examples">
<h3 class="title">Examples</h3>
<div class="example" id="example-4608">
<p><strong>Example #1 <span class="function"><a href="syncsharedmemory.construct.html" class="function">SyncSharedMemory::__construct()</a></span> example</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">// You will probably need to protect shared memory with other synchronization objects.<br />// Shared memory goes away when the last reference to it disappears.<br /></span><span style="color: #0000BB">$mem </span><span style="color: #007700">= new </span><span style="color: #0000BB">SyncSharedMemory</span><span style="color: #007700">(</span><span style="color: #DD0000">"AppReportName"</span><span style="color: #007700">, </span><span style="color: #0000BB">1024</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">$mem</span><span style="color: #007700">-></span><span style="color: #0000BB">first</span><span style="color: #007700">())<br />{<br /> </span><span style="color: #FF8000">// Do first time initialization work here.<br /></span><span style="color: #007700">}<br /><br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">$mem</span><span style="color: #007700">-></span><span style="color: #0000BB">write</span><span style="color: #007700">(</span><span style="color: #DD0000">"report.txt"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">$mem</span><span style="color: #007700">-></span><span style="color: #0000BB">read</span><span style="color: #007700">(</span><span style="color: #0000BB">3</span><span style="color: #007700">, -</span><span style="color: #0000BB">4</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></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>
string(3) "ort"
</pre></div>
</div>
</div>
</div>
<div class="refsect1 seealso" id="refsect1-syncsharedmemory.read-seealso">
<h3 class="title">See Also</h3>
<ul class="simplelist">
<li class="member"><span class="methodname"><a href="syncsharedmemory.construct.html" class="methodname" rel="rdfs-seeAlso">SyncSharedMemory::__construct()</a> - Constructs a new SyncSharedMemory object</span></li>
<li class="member"><span class="methodname"><a href="syncsharedmemory.first.html" class="methodname" rel="rdfs-seeAlso">SyncSharedMemory::first()</a> - Check to see if the object is the first instance system-wide of named shared memory</span></li>
<li class="member"><span class="methodname"><a href="syncsharedmemory.write.html" class="methodname" rel="rdfs-seeAlso">SyncSharedMemory::write()</a> - Copy data to named shared memory</span></li>
<li class="member"><span class="methodname"><strong>SyncSharedMemory::read()</strong></span></li>
</ul>
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