
<pre>
void negate(int *x) {
  *x = -(*x);
}
</pre>
</div>

<p>
you can use <tt>INOUT</tt> like this:
</p>

<div class="code">
<pre>
%include "typemaps.i"
...
void negate(int *INOUT);
</pre>
</div>

<p>
In Tcl, a mutated parameter shows up as a return value.  For example:
</p>

<div class="code">
<pre>
set a [negate 3]
puts $a
-3
</pre>
</div>

<p>
The most common use of these special typemap rules is to handle functions that
return more than one value.   For example, sometimes a function returns a result
a