How to Use the codedoc Utility

Michael R Sweet

Copyright © 2003-2019 by Michael R Sweet


Codedoc is a general-purpose utility which scans HTML, markdown, C, and C++ source files to produce EPUB, HTML, and man page documentation that can be read by humans. Unlike popular C/C++ documentation generators like Doxygen or Javadoc, Codedoc uses in-line comments rather than comment headers, allowing for more "natural" code documentation. Additional markdown documentation content can be included to make the generated documentation even more useful and complete.

Codedoc is licensed under the Apache License Version 2.0 with an exception to allow linking against GPL2/LGPL2-only software. See the files "LICENSE" and "NOTICE" in the source code archive or Git repository for more information.


Codedoc was originally part of the Mini-XML project (as "codedoc") and was developed specifically to generate the API documentation for Mini-XML and CUPS. It is now much more general purpose.

Running Codedoc

Codedoc produces HTML documentation by default. 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 "documentation.html":

codedoc *.h *.c >documentation.html

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 "documentation.xml" in addition to the HTML file:

codedoc documentation.xml *.h *.c >documentation.html

The --no-output option disables the default HTML output:

codedoc --no-output documentation.xml *.h *.c

You can then run codedoc again with the XML file alone to generate the HTML documentation:

codedoc documentation.xml >documentation.html

Creating Man Pages

The --man name option tells codedoc to create a man page instead of HTML documentation, for example:

codedoc --man libexample *.h *.c >libexample.3
codedoc --man libexample documentation.xml *.h *.c >libexample.3
codedoc --man libexample documentation.xml >libexample.3

Creating EPUB Books

The --epub filename.epub option tells codedoc to create an EPUB book containing the HTML documentation, for example:

codedoc --epub documentation.epub *.h *.c
codedoc --epub documentation.epub documentation.xml *.h *.c
codedoc --epub documentation.epub documentation.xml

Adding Content and Metadata

Codedoc supports several options for adding content and metadata to the generated documentation:

  • --author "name": Sets the author name
  • --body filename: Inserts the named file between the table of contents and API documentation; the file can be markdown, HTML, or man source
  • --copyright "copyright text": Sets the copyright string
  • --coverimage filename.png: Uses the specified cover page image file
  • --css filename.css: Uses the specified style sheet file (HTML and EPUB output)
  • --footer filename: Appends the named file after the API documentation; the file can be markdown, HTML, or man source
  • --header filename: Inserts the named file before the table of contents; the file can be markdown, HTML, or man source
  • --section "{name,number}": Sets the section/category name (HTML and EPUB output) or section number (man page output)
  • --title "title text'; Sets the title text

Annotating Your C/C++ Code

Codedoc looks for in-line comments to describe the functions, types, and constants in your code. Codedoc documents all public names it finds in your source files - any names starting with the underscore character () or names that are documented with the @private@ directive are treated as private and are not documented.

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:

/* 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 */
    const char *key, /* Key string */
    const char *val) /* Value string */

Codedoc also knows to remove extra asterisks (*) from the comment string, so the comment string:

 * 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.

will be shown as:

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.

@ Directives in Comments

Comments can also include the following special @name ...@ directive strings:

  • @code text@: formats the text as code
  • @deprecated@: flags the item as deprecated to discourage its use
  • @exclude format[,...,format]@: excludes the item from the documentation in the specified formats: "all" for all formats, "epub" for EPUB books, "html" for HTML output, and "man" for man page output
  • @link name@: creates a hyperlink to the named function, type, etc.
  • @private@: flags the item as private so it will not be included in the documentation
  • @since ...@: flags the item as new since a particular release. The text following the @since up to the closing @ is highlighted in the generated documentation, e.g. @since libexample 1.1@.

EPUB and HTML Stylesheets

Codedoc makes use of a CSS stylesheet for EPUB and HTML output. The default stylesheet should be usable for both display and printing, but you can override it using the --css option, for example:

codedoc --epub documentation.epub --css filename.css documentation.xml *.h *.c


Since EPUB uses XHTML (which is case-sensitive), your stylesheet should always use lowercase element names ("pre", not "PRE", etc.)

CSS Classes

The following CSS classes are used to group the sections in the generated documentation:

The body of the documentation
<div class="body">
Centered text in cell
<td class="center">
A class
<hN class="class">
Wrapped monospace code text
<p class="code">
A list of constants
<hN class="constants">
The table of contents
<div class="contents">

(first level)
<ul class="contents">
Short description
<p class="description">

(in table)
<td class="description">
Additional description
<p class="discussion">

<hN class="discussion">

(in table)
<td class="discussion">
An enumeration type
<hN class="enumeration">
The footer of the documentation
<div class="footer">
A global function
<hN class="function">
The header of the documentation
<div class="header">
Availability information
<span class="info">
Left-aligned text in cell
<td class="left">
A table list
<table class="list">
A list of class/struct members
<table class="members">
A class or structure method
<hN class="method">
A list of function parameters
<hN class="parameters">
The return value of a function
<hN class="returnvalue">
Right-aligned text in cell
<td class="right">
A structure
<hN class="struct">
Second-level contents
<ul class="subcontents">
A title
<hN class="title">
A typedef
<hN class="typedef">
A union
<hN class="union">
A global variable
<hN class="variable">

Default Stylesheet

body, p, h1, h2, h3, h4, h5, h6 {
  font-family: sans-serif;
h1, h2, h3, h4, h5, h6 {
  font-weight: bold;
  page-break-inside: avoid;
h1 {
  font-size: 250%;
  margin: 0;
h2 {
  font-size: 250%;
  margin-top: 1.5em;
h3 {
  font-size: 200%;
  margin-bottom: 0.5em;
  margin-top: 1.5em;
h4 {
  font-size: 150%;
  margin-bottom: 0.5em;
  margin-top: 1.5em;
h5 {
  font-size: 125%;
  margin-bottom: 0.5em;
  margin-top: 1.5em;
h6 {
  font-size: 110%;
  margin-bottom: 0.5em;
  margin-top: 1.5em;
div.header h1, div.header p {
  text-align: center;
div.contents, div.body, div.footer {
  page-break-before: always;
.class, .enumeration, .function, .struct, .typedef, .union {
  border-bottom: solid 2px gray;
.description {
  margin-top: 0.5em;
.function {
  margin-bottom: 0;
blockquote {
  border: solid thin gray;
  box-shadow: 3px 3px 5px rgba(0,0,0,0.5);
  padding: 0px 10px;
  page-break-inside: avoid;
p code, li code, p.code, pre, ul.code li {
  background: rgba(127,127,127,0.1);
  border: thin dotted gray;
  font-family: monospace;
  font-size: 90%;
  hyphens: manual;
  -webkit-hyphens: manual;
  page-break-inside: avoid;
p.code, pre, ul.code li {
  padding: 10px;
p code, li code {
  padding: 2px 5px;
a:link, a:visited {
  text-decoration: none;
} {
  background: black;
  border: solid thin black;
  color: white;
  font-size: 80%;
  font-style: italic;
  font-weight: bold;
  white-space: nowrap;
h1, h2, h3, h4 {
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
  float: right;
  padding: 3px 6px;
ul.code, ul.contents, ul.subcontents {
  list-style-type: none;
  margin: 0;
  padding-left: 0;
ul.code li {
  margin: 0;
ul.contents > li {
  margin-top: 1em;
ul.contents li ul.code, ul.contents li ul.subcontents {
  padding-left: 2em;
table {
  border-collapse: collapse;
  border-spacing: 0;
td {
  border: solid 1px #666;
  padding: 5px 10px;
  vertical-align: top;
td.left {
  text-align: left;
} {
  text-align: center;
td.right {
  text-align: right;
th {
  border-bottom: solid 2px #000;
  padding: 1px 5px;
  text-align: center;
  vertical-align: bottom;
tr:nth-child(odd) {
  background: rgba(127,127,127,0.1);
table.list {
  border-collapse: collapse;
  width: 100%;
table.list th {
  border-bottom: none;
  border-right: 2px solid gray;
  font-family: monospace;
  padding: 5px 10px 5px 2px;
  text-align: right;
  vertical-align: top;
table.list td {
  border: none;
  padding: 5px 2px 5px 10px;
  text-align: left;
  vertical-align: top;
h2.title, h3.title {
  border-bottom: solid 2px black;