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<html><head><title>XLISP *unbound*</title>
<link rel="stylesheet" type="text/css" href="reference.css">
</head>
<body>
<a href="../start.htm">Nyquist / XLISP 2.0</a> -
<a href="../manual/contents.htm">Contents</a> |
<a href="../tutorials/tutorials.htm">Tutorials</a> |
<a href="../examples/examples.htm">Examples</a> |
<a href="reference-index.htm">Reference</a>
<hr>
<h1>*unbound*</h1>
<hr>
<p><table cellpadding="0" cellspacing="0" style="margin-left:10px"><tbody>
<tr valign="top">
<td><nobr>Type:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>system constant</nobr></td>
</tr>
<tr valign="top">
<td><nobr>Source:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>xlinit.c, xlsym.c</nobr></td>
</tr>
</tbody></table></p>
<h2>Syntax</h2>
<dl>
<dt> *unbound*</dt>
</dl>
<h2>Description</h2>
<p>The *unbound* system constant is used to indicate when a symbol has no
value. *unbound* is set to the value *unbound*. This means that the system
thinks the symbol *unbound* has no value.</p>
<h2>Examples</h2>
<pre class="example">
*unbound* <font color="#008844">; error: unbound variable</font>
(setq a 5) <font color="#008844">; returns 5</font>
a <font color="#008844">; returns 5</font>
(setq a '*unbound*) <font color="#008844">; returns *UNBOUND*</font>
a <font color="#008844">; error: unbound variable</font>
</pre>
<p>See the
<a href="../manual/xlisp-man-011.htm#unbound">*unbound*</a>
system constant in the <nobr>XLISP 2.0</nobr> manual.</p>
<p><nobr> <a href="#top">Back to Top</nobr></a></p>
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