Sophie: sbcl-1.0.31-1mdv2010.0 i586

sbcl-1.0.31-1mdv2010.0.i586.rpm

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<h4 class="subsection">8.4.1 Local Foreign Variables</h4>

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&mdash; Macro: <b>sb-alien:with-alien</b><var> var-definitions &amp;body body<a name="index-sb_002dalien_003awith_002dalien-290"></a></var><br>
<blockquote><p><a name="index-with_002dalien-291"></a>
The <code>with-alien</code> macro establishes local foreign variables with
the specified alien types and names.  This form is analogous to
defining a local variable in C: additional storage is allocated, and
the initial value is copied.  This form is less analogous to
<code>LET</code>-allocated Lisp variables, since the variables can't be
captured in closures: they live only for the dynamic extent of the
body, and referring to them outside is a gruesome error.

        <p>The <var>var-definitions</var> argument is a list of
variable definitions, each of the form
     <pre class="lisp">          (<var>name</var> <var>type</var> &amp;optional <var>initial-value</var>)
</pre>
        <p>The names of the variables are established as symbol-macros; the
bindings have lexical scope, and may be assigned with <code>setq</code> or
<code>setf</code>.

        <p>The <code>with-alien</code> macro also establishes a new scope for named
structures and unions.  Any <var>type</var> specified for a variable may
contain named structure or union types with the slots specified. 
Within the lexical scope of the binding specifiers and body, a locally
defined foreign structure type <var>foo</var> can be referenced by its name
using <code>(struct </code><var>foo</var><code>)</code>. 
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