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<h1 align='right'><a name='MXMLDOC'><img src="4.gif" align="right"
hspace="10" width="100" height="100" alt="4"></a>Using the mxmldoc
Utility</h1>

<p>This chapter describes how to use <tt>mxmldoc(1)</tt> program to
automatically generate documentation from C and C++ source
files.</p>


<h2>The Basics</h2>

<p>Originally developed to generate the Mini-XML and CUPS API
documentation, <tt>mxmldoc</tt> is now a general-purpose utility
which scans C and C++ source files to produce HTML and man page
documentation along with an XML file representing the functions,
types, and definitions in those source files. Unlike popular
documentation generators like Doxygen or Javadoc, <tt>mxmldoc</tt>
uses in-line comments rather than comment headers, allowing for more
"natural" code documentation.</p>

<p>By default, <tt>mxmldoc</tt> produces HTML documentation. For
example, the following command will scan all of the C source and
header files in the current directory and produce a HTML
documentation file called <var>filename.html</var>:</p>

<pre>
    <kbd>mxmldoc *.h *.c &gt;filename.html ENTER</kbd>
</pre>

<p>You can also specify an XML file to create which contains all of
the information from the source files. For example, the following
command creates an XML file called <var>filename.xml</var> in
addition to the HTML file:</p>

<pre>
    <kbd>mxmldoc filename.xml *.h *.c &gt;filename.html ENTER</kbd>
</pre>

<p>The <tt>--no-output</tt> option disables the normal HTML
output:</p>

<pre>
    <kbd>mxmldoc --no-output filename.xml *.h *.c ENTER</kbd>
</pre>

<p>You can then run <tt>mxmldoc</tt> again with the XML file alone
to generate the HTML documentation:</p>

<pre>
    <kbd>mxmldoc filename.xml &gt;filename.html ENTER</kbd>
</pre>

<h3>Creating Man Pages</h3>

<p>The <tt>--man filename</tt> option tells <tt>mxmldoc</tt> to
create a man page instead of HTML documentation, for example:</p>

<pre>
    <kbd>mxmldoc --man filename filename.xml \
        &gt;filename.man ENTER</kbd>

    <kbd>mxmldoc --man filename *.h *.c \
        &gt;filename.man ENTER</kbd>
</pre>

<h3>Creating Xcode Documentation Sets</h3>

<p>The <tt>--docset directory.docset</tt> option tells <tt>mxmldoc</tt> to
create an Xcode documentation set containing the HTML documentation, for
example:</p>

<pre>
    <kbd>mxmldoc --docset foo.docset *.h *.c foo.xml ENTER</kbd>
</pre>

<p>Xcode documentation sets can only be built on Mac OS X with Xcode 3.0 or
higher installed.</p>


<h2>Commenting Your Code</h2>

<p>As noted previously, <tt>mxmldoc</tt> looks for in-line comments
to describe the functions, types, and constants in your code.
<tt>Mxmldoc</tt> will document all public names it finds in your
source files - any names starting with the underscore character (_) 
or names that are documented with the <A
HREF="#ATDIRECTIVES">@private@</A> directive are treated as private
and are not documented.</p>

<p>Comments appearing directly before a function or type definition
are used to document that function or type. Comments appearing after
argument, definition, return type, or variable declarations are used
to document that argument, definition, return type, or variable. For
example, the following code excerpt defines a key/value structure
and a function that creates a new instance of that structure:</p> 

<pre>
    /* A key/value pair. This is used with the
       dictionary structure. */

    struct keyval
    {
      char *key; /* Key string */
      char *val; /* Value string */
    };

    /* Create a new key/value pair. */

    struct keyval * /* New key/value pair */
    new_keyval(
        const char *key, /* Key string */
	const char *val) /* Value string */
    {
      ...
    }
</pre>

<p><tt>Mxmldoc</tt> also knows to remove extra asterisks (*) from
the comment string, so the comment string:</p>

<pre>
    /*
     * Compute the value of PI.
     *
     * The function connects to an Internet server
     * that streams audio of mathematical monks
     * chanting the first 100 digits of PI.
     */
</pre>

<p>will be shown as:</p>

<pre>
    Compute the value of PI.

    The function connects to an Internet server
    that streams audio of mathematical monks
    chanting the first 100 digits of PI.
</pre>

<p><a name="ATDIRECTIVES">Comments</a> can also include the
following special <tt>@name ...@</tt> directive strings:</p>

<ul>

	<li><tt>@deprecated@</tt> - flags the item as deprecated to
	discourage its use</li>

	<li><tt>@private@</tt> - flags the item as private so it
	will not be included in the documentation</li>

	<li><tt>@since ...@</tt> - flags the item as new since a
	particular release. The text following the <tt>@since</tt>
	up to the closing <tt>@</tt> is highlighted in the generated
	documentation, e.g. <tt>@since Mini-XML 2.7@</tt>.</li>

</ul>


<!-- NEED 10 -->
<h2>Titles, Sections, and Introductions</h2>

<p><tt>Mxmldoc</tt> also provides options to set the title, section,
and introduction text for the generated documentation. The
<tt>--title text</tt> option specifies the title for the
documentation. The title string is usually put in quotes:</p>

<pre>
    <kbd>mxmldoc filename.xml \
        --title "My Famous Documentation" \
        &gt;filename.html ENTER</kbd>
</pre>

<p>The <tt>--section name</tt> option specifies the section for
the documentation. For HTML documentation, the name is placed in
a HTML comment such as:</p>

<pre>
    &lt;!-- SECTION: name -->
</pre>

<p>For man pages, the section name is usually just a number ("3"),
or a number followed by a vendor name ("3acme"). The section name is
used in the <tt>.TH</tt> directive in the man page:</p>

<pre>
    .TH mylibrary 3acme "My Title" ...
</pre>

<p>The default section name for man page output is "3". There is no
default section name for HTML output.</p>

<p>Finally, the <tt>--intro filename</tt> option specifies a file to
embed after the title and section but before the generated
documentation. For HTML documentation, the file must consist of
valid HTML without the usual <tt>DOCTYPE</tt>, <tt>html</tt>, and
<tt>body</tt> elements. For man page documentation, the file must
consist of valid <tt>nroff(1)</tt> text.</p>

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