<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>deref-array</title><link rel="stylesheet" href="ecl.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"><link rel="home" href="index.html" title="The ECL manual"><link rel="up" href="rn02.html" title="Aggregate Types"><link rel="prev" href="rn02re53.html" title="def-array-pointer"><link rel="next" href="rn02re55.html" title="def-union"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><code class="function">deref-array</code></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="rn02re53.html">Prev</a> </td><th width="60%" align="center">Aggregate Types</th><td width="20%" align="right"> <a accesskey="n" href="rn02re55.html">Next</a></td></tr></table><hr></div><div class="refentry" title="deref-array"><a name="uffi.deref-array"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p><code class="function">deref-array</code> — Deference an array.
<b>Macro</b></p></div><div class="refsynopsisdiv" title="Syntax"><h2>Syntax</h2><pre class="synopsis">
<code class="function">deref-array</code> <em class="replaceable"><code>array type position</code></em> => <span class="returnvalue">value</span>
</pre></div><div class="refsect1" title="Arguments and Values"><a name="id687764"></a><h2>Arguments and Values</h2><div class="variablelist"><table border="0"><col align="left" valign="top"><tbody><tr><td><p><span class="term"><em class="parameter"><code>array</code></em></span></p></td><td><p>A foreign array.
</p></td></tr><tr><td><p><span class="term"><em class="parameter"><code>type</code></em></span></p></td><td><p>The foreign type of the array.
</p></td></tr><tr><td><p><span class="term"><em class="parameter"><code>position</code></em></span></p></td><td><p>An integer specifying the position to retrieve from
the array.
</p></td></tr><tr><td><p><span class="term"><span class="returnvalue">value</span></span></p></td><td><p>The value stored in the position of the array.
</p></td></tr></tbody></table></div></div><div class="refsect1" title="Description"><a name="id687839"></a><h2>Description</h2><p>
Dereferences (retrieves) the value of an array element.
</p></div><div class="refsect1" title="Examples"><a name="id687850"></a><h2>Examples</h2><pre class="screen">
(def-array-pointer ca :char)
(let ((fs (convert-to-foreign-string "ab")))
(values (null-char-p (deref-array fs 'ca 0))
(null-char-p (deref-array fs 'ca 2))))
=> <code class="constant">NIL</code>
<code class="constant">T</code></pre></div><div class="refsect1" title="Notes"><a name="id687870"></a><h2>Notes</h2><p>
The TYPE argument is ignored for CL implementations other than
AllegroCL. If you want to cast a pointer to another type use
WITH-CAST-POINTER together with DEREF-POINTER/DEREF-ARRAY.
</p></div><div class="refsect1" title="Side Effects"><a name="id687881"></a><h2>Side Effects</h2><p>None.</p></div><div class="refsect1" title="Affected by"><a name="id687892"></a><h2>Affected by</h2><p>None.</p></div><div class="refsect1" title="Exceptional Situations"><a name="id687902"></a><h2>Exceptional Situations</h2><p>None.</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="rn02re53.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="rn02.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="rn02re55.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><code class="function">def-array-pointer</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <code class="function">def-union</code></td></tr></table></div></body></html>
