FindDoxygen

Doxygen is a documentation generation tool (see http://www.doxygen.org). This module looks for Doxygen and some optional tools it supports. These tools are enabled as components in the find_package() command:

dot

Graphviz dot utility used to render various graphs.

mscgen

Message Chart Generator utility used by Doxygen’s \msc and \mscfile commands.

dia

Dia the diagram editor used by Doxygen’s \diafile command.

Examples:

# Require dot, treat the other components as optional
find_package(Doxygen
             REQUIRED dot
             OPTIONAL_COMPONENTS mscgen dia)

The following variables are defined by this module:

DOXYGEN_FOUND

True if the doxygen executable was found.

DOXYGEN_VERSION

The version reported by doxygen --version.

The module defines IMPORTED targets for Doxygen and each component found. These can be used as part of custom commands, etc. and should be preferred over old-style (and now deprecated) variables like DOXYGEN_EXECUTABLE. The following import targets are defined if their corresponding executable could be found (the component import targets will only be defined if that component was requested):

Doxygen::doxygen
Doxygen::dot
Doxygen::mscgen
Doxygen::dia

Functions

doxygen_add_docs

This function is intended as a convenience for adding a target for generating documentation with Doxygen. It aims to provide sensible defaults so that projects can generally just provide the input files and directories and that will be sufficient to give sensible results. The function supports the ability to customize the Doxygen configuration used to build the documentation.

doxygen_add_docs(targetName
    [filesOrDirs...]
    [ALL]
    [USE_STAMP_FILE]
    [WORKING_DIRECTORY dir]
    [COMMENT comment])

The function constructs a Doxyfile and defines a custom target that runs Doxygen on that generated file. The listed files and directories are used as the INPUT of the generated Doxyfile and they can contain wildcards. Any files that are listed explicitly will also be added as SOURCES of the custom target so they will show up in an IDE project’s source list.

So that relative input paths work as expected, by default the working directory of the Doxygen command will be the current source directory (i.e. CMAKE_CURRENT_SOURCE_DIR). This can be overridden with the WORKING_DIRECTORY option to change the directory used as the relative base point. Note also that Doxygen’s default behavior is to strip the working directory from relative paths in the generated documentation (see the STRIP_FROM_PATH Doxygen config option for details).

If provided, the optional comment will be passed as the COMMENT for the add_custom_target() command used to create the custom target internally.

If ALL is set, the target will be added to the default build target.

If USE_STAMP_FILE is set, the custom command defined by this function will create a stamp file with the name <targetName>.stamp in the current binary directory whenever doxygen is re-run. With this option present, all items in <filesOrDirs> must be files (i.e. no directories, symlinks or wildcards) and each of the files must exist at the time doxygen_add_docs() is called. An error will be raised if any of the items listed is missing or is not a file when USE_STAMP_FILE is given. A dependency will be created on each of the files so that doxygen will only be re-run if one of the files is updated. Without the USE_STAMP_FILE option, doxygen will always be re-run if the <targetName> target is built regardless of whether anything listed in <filesOrDirs> has changed.

The contents of the generated Doxyfile can be customized by setting CMake variables before calling doxygen_add_docs(). Any variable with a name of the form DOXYGEN_<tag> will have its value substituted for the corresponding <tag> configuration option in the Doxyfile. See the Doxygen documentation for the full list of supported configuration options.

Some of Doxygen’s defaults are overridden to provide more appropriate behavior for a CMake project. Each of the following will be explicitly set unless the variable already has a value before doxygen_add_docs() is called (with some exceptions noted):

DOXYGEN_HAVE_DOT

Set to YES if the dot component was requested and it was found, NO otherwise. Any existing value of DOXYGEN_HAVE_DOT is ignored.

DOXYGEN_DOT_MULTI_TARGETS

Set to YES by this module (note that this requires a dot version newer than 1.8.10). This option is only meaningful if DOXYGEN_HAVE_DOT is also set to YES.

DOXYGEN_GENERATE_LATEX

Set to NO by this module.

DOXYGEN_WARN_FORMAT

For Visual Studio based generators, this is set to the form recognized by the Visual Studio IDE: $file($line) : $text. For all other generators, Doxygen’s default value is not overridden.

DOXYGEN_PROJECT_NAME

Populated with the name of the current project (i.e. PROJECT_NAME).

DOXYGEN_PROJECT_NUMBER

Populated with the version of the current project (i.e. PROJECT_VERSION).

DOXYGEN_PROJECT_BRIEF

Populated with the description of the current project (i.e. PROJECT_DESCRIPTION).

DOXYGEN_INPUT

Projects should not set this variable. It will be populated with the set of files and directories passed to doxygen_add_docs(), thereby providing consistent behavior with the other built-in commands like add_executable(), add_library() and add_custom_target(). If a variable named DOXYGEN_INPUT is set by the project, it will be ignored and a warning will be issued.

DOXYGEN_RECURSIVE

Set to YES by this module.

DOXYGEN_EXCLUDE_PATTERNS

If the set of inputs includes directories, this variable will specify patterns used to exclude files from them. The following patterns are added by doxygen_add_docs() to ensure CMake-specific files and directories are not included in the input. If the project sets DOXYGEN_EXCLUDE_PATTERNS, those contents are merged with these additional patterns rather than replacing them:

*/.git/*
*/.svn/*
*/.hg/*
*/CMakeFiles/*
*/_CPack_Packages/*
DartConfiguration.tcl
CMakeLists.txt
CMakeCache.txt

DOXYGEN_OUTPUT_DIRECTORY

Set to CMAKE_CURRENT_BINARY_DIR by this module. Note that if the project provides its own value for this and it is a relative path, it will be converted to an absolute path relative to the current binary directory. This is necessary because doxygen will normally be run from a directory within the source tree so that relative source paths work as expected. If this directory does not exist, it will be recursively created prior to executing the doxygen commands.

To change any of these defaults or override any other Doxygen config option, set relevant variables before calling doxygen_add_docs(). For example:

set(DOXYGEN_GENERATE_HTML NO)
set(DOXYGEN_GENERATE_MAN YES)

doxygen_add_docs(
    doxygen
    ${PROJECT_SOURCE_DIR}
    COMMENT "Generate man pages"
)

A number of Doxygen config options accept lists of values, but Doxygen requires them to be separated by whitespace. CMake variables hold lists as a string with items separated by semi-colons, so a conversion needs to be performed. The doxygen_add_docs() command specifically checks the following Doxygen config options and will convert their associated CMake variable’s contents into the required form if set.

ABBREVIATE_BRIEF
ALIASES
CITE_BIB_FILES
DIAFILE_DIRS
DOTFILE_DIRS
DOT_FONTPATH
ENABLED_SECTIONS
EXAMPLE_PATH
EXAMPLE_PATTERNS
EXCLUDE
EXCLUDE_PATTERNS
EXCLUDE_SYMBOLS
EXPAND_AS_DEFINED
EXTENSION_MAPPING
EXTRA_PACKAGES
EXTRA_SEARCH_MAPPINGS
FILE_PATTERNS
FILTER_PATTERNS
FILTER_SOURCE_PATTERNS
HTML_EXTRA_FILES
HTML_EXTRA_STYLESHEET
IGNORE_PREFIX
IMAGE_PATH
INCLUDE_FILE_PATTERNS
INCLUDE_PATH
INPUT
LATEX_EXTRA_FILES
LATEX_EXTRA_STYLESHEET
MATHJAX_EXTENSIONS
MSCFILE_DIRS
PLANTUML_INCLUDE_PATH
PREDEFINED
QHP_CUST_FILTER_ATTRS
QHP_SECT_FILTER_ATTRS
STRIP_FROM_INC_PATH
STRIP_FROM_PATH
TAGFILES
TCL_SUBST

The following single value Doxygen options will be quoted automatically if they contain at least one space:

CHM_FILE
DIA_PATH
DOCBOOK_OUTPUT
DOCSET_FEEDNAME
DOCSET_PUBLISHER_NAME
DOT_FONTNAME
DOT_PATH
EXTERNAL_SEARCH_ID
FILE_VERSION_FILTER
GENERATE_TAGFILE
HHC_LOCATION
HTML_FOOTER
HTML_HEADER
HTML_OUTPUT
HTML_STYLESHEET
INPUT_FILTER
LATEX_FOOTER
LATEX_HEADER
LATEX_OUTPUT
LAYOUT_FILE
MAN_OUTPUT
MAN_SUBDIR
MATHJAX_CODEFILE
MSCGEN_PATH
OUTPUT_DIRECTORY
PERL_PATH
PLANTUML_JAR_PATH
PROJECT_BRIEF
PROJECT_LOGO
PROJECT_NAME
QCH_FILE
QHG_LOCATION
QHP_CUST_FILTER_NAME
QHP_VIRTUAL_FOLDER
RTF_EXTENSIONS_FILE
RTF_OUTPUT
RTF_STYLESHEET_FILE
SEARCHDATA_FILE
USE_MDFILE_AS_MAINPAGE
WARN_FORMAT
WARN_LOGFILE
XML_OUTPUT

There are situations where it may be undesirable for a particular config option to be automatically quoted by doxygen_add_docs(), such as ALIASES which may need to include its own embedded quoting. The DOXYGEN_VERBATIM_VARS variable can be used to specify a list of Doxygen variables (including the leading DOXYGEN_ prefix) which should not be quoted. The project is then responsible for ensuring that those variables’ values make sense when placed directly in the Doxygen input file. In the case of list variables, list items are still separated by spaces, it is only the automatic quoting that is skipped. For example, the following allows doxygen_add_docs() to apply quoting to DOXYGEN_PROJECT_BRIEF, but not each item in the DOXYGEN_ALIASES list (bracket syntax can also be used to make working with embedded quotes easier):

set(DOXYGEN_PROJECT_BRIEF "String with spaces")
set(DOXYGEN_ALIASES
    [[somealias="@some_command param"]]
    "anotherAlias=@foobar"
)
set(DOXYGEN_VERBATIM_VARS DOXYGEN_ALIASES)

The resultant Doxyfile will contain the following lines:

PROJECT_BRIEF = "String with spaces"
ALIASES       = somealias="@some_command param" anotherAlias=@foobar

Deprecated Result Variables

For compatibility with previous versions of CMake, the following variables are also defined but they are deprecated and should no longer be used:

DOXYGEN_EXECUTABLE

The path to the doxygen command. If projects need to refer to the doxygen executable directly, they should use the Doxygen::doxygen import target instead.

DOXYGEN_DOT_FOUND

True if the dot executable was found.

DOXYGEN_DOT_EXECUTABLE

The path to the dot command. If projects need to refer to the dot executable directly, they should use the Doxygen::dot import target instead.

DOXYGEN_DOT_PATH

The path to the directory containing the dot executable as reported in DOXYGEN_DOT_EXECUTABLE. The path may have forward slashes even on Windows and is not suitable for direct substitution into a Doxyfile.in template. If you need this value, get the IMPORTED_LOCATION property of the Doxygen::dot target and use get_filename_component() to extract the directory part of that path. You may also want to consider using file(TO_NATIVE_PATH) to prepare the path for a Doxygen configuration file.

Deprecated Hint Variables

DOXYGEN_SKIP_DOT

This variable has no effect for the component form of find_package. In backward compatibility mode (i.e. without components list) it prevents the finder module from searching for Graphviz’s dot utility.