Assuming you have the following html file:
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
<head>
<title>Foobar</title>
</head>
<body>
<h1>Foobar</h1>
Hello everybody!
<!-- code2html add -l c /home/weasel/foobar.c -->
That's it.
</body>
</html>
After running 'code2html -p thisfile.html' your file will look like this:
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
<head>
<title>Foobar</title>
</head>
<body>
<h1>Foobar</h1>
Hello everybody!
<!-- code2html add -l c /home/weasel/foobar.c -->
< the syntax highlighted code of /home/weasel/foobar.c is here >
That's it.
</body>
</html>
To see a real world example have a look at the examples: