+ <refentry id="with-foreign-object">
+ <refnamediv>
+ <refname>with-foreign-object</refname>
+ <refpurpose>Wraps the allocation of a foreign object around a body of code.
+ </refpurpose>
+ <refclass>Macro</refclass>
+ </refnamediv>
+ <refsynopsisdiv>
+ <title>Syntax</title>
+ <synopsis>
+ <function>with-foreign-object</function> <replaceable>(var type) &body body</replaceable> => <returnvalue>form-return</returnvalue>
+ </synopsis>
+ </refsynopsisdiv>
+ <refsect1>
+ <title>Arguments and Values</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>var</parameter></term>
+ <listitem>
+ <para>The variable name to bind.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>type</parameter></term>
+ <listitem>
+ <para>The type of foreign object to allocate. This parameter is evaluated.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><returnvalue>form-return</returnvalue></term>
+ <listitem>
+ <para>The result of evaluating the <parameter>body</parameter>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>
+This function wraps the allocation, binding, and destruction of a foreign object.
+On &cmucl; and
+&lw; platforms the object is stack allocated for efficiency. Benchmarks show that &acl; performs
+much better with static allocation.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Examples</title>
+ <programlisting>
+(defun gethostname2 ()
+ "Returns the hostname"
+ (uffi:with-foreign-object (name '(:array :unsigned-char 256))
+ (if (zerop (c-gethostname (uffi:char-array-to-pointer name) 256))
+ (uffi:convert-from-foreign-string name)
+ (error "gethostname() failed."))))
+ </programlisting>
+ </refsect1>
+ <refsect1>
+ <title>Side Effects</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Affected by</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Exceptional Situations</title>
+ <para>None.</para>
+ </refsect1>
+ </refentry>
+