/****************************************************************************** * * * * Copyright (C) 1997-2001 by Dimitri van Heesch. * * Permission to use, copy, modify, and distribute this software and its * documentation under the terms of the GNU General Public License is hereby * granted. No representations are made about the suitability of this software * for any purpose. It is provided "as is" without express or implied warranty. * See the GNU General Public License for more details. * * Documents produced by Doxygen are derivative works derived from the * input used in their production; they are not affected by this license. * */ /*! \page docblocks Documenting the code \subsection specialblock Special documentation blocks The following types of special documentation blocks are supported by doxygen: Doxygen only allows one brief and one detailed description. If there is one brief description before a declaration and one before a definition, only the one before the \e declaration will be used. If the same situation occurs for a detailed description, the one before the \e definition is preferred and the one before the declaration will be ignored. Here is an example of a documented piece of C++ code using the Qt style: \verbinclude qtstyle.cpp \htmlonly Click here for the corresponding HTML documentation that is generated by doxygen. \endhtmlonly The one-line comments should contain a brief description, whereas the multi-line comment blocks contain a more detailed description. Note that consecutive one-line comments are merged together in one brief description. The brief descriptions are included in the member overview of a class, namespace or file and are printed using a small italic font (this description can be hidden by setting \ref cfg_brief_member_desc "BRIEF_MEMBER_DESC" to \c NO in the config file). By default the brief descriptions become the first sentence of the detailed descriptions (but this can be changed by setting the \ref cfg_repeat_brief "REPEAT_BRIEF" tag to \c NO). Both the brief and the detailed descriptions are optional for the Qt style. By default a JavaDoc style documentation block behaves the same way as a Qt style documentation block. This is not according the JavaDoc specification however, where the first sentence of the documentation block is automatically treated as a brief description. To enable this behaviour you should set \ref cfg_javadoc_autobrief "JAVADOC_AUTOBRIEF" to YES in the configuration file. If you enable this option and want to put a dot in the middle of a sentence without ending it, you should put a backslash and a space after it. Here is an example: \verbatim /** Brief description (e.g.\ using only a few words). Details follow. */ \endverbatim Here is the same piece of code as shown above, this time documented using the JavaDoc style and \ref cfg_javadoc_autobrief "JAVADOC_AUTOBRIEF" set to YES: \verbinclude jdstyle.cpp \htmlonly Click here for the corresponding HTML documentation that is generated by doxygen. \endhtmlonly Unlike most other documentation systems, doxygen also allows you to put the documentation of members (including global functions) in front of the \e definition. This way the documentation can be placed in the source file instead of the header file. This keeps the header file compact, and allows the implementer of the members more direct access to the documentation. As a compromise the brief description could be placed before the declaration and the detailed description before the member definition. \par Note: Each entity can only have \e one brief and \e one detailed description. If you specify more than one comment block of the same type, only one will be used, and all others are ignored! \subsection structuralcommands Structural commands So far we have assumed that the documentation blocks are always located in front of the declaration or definition of a file, class or namespace or in front of one of its members. Although this is often comfortable, it may sometimes be better to put the documentation somewhere else. For some types of documentation blocks (like file documentation) this is even required. Doxygen allows you to put your documentation blocks practically anywhere (the exception is inside the body of a function or inside a normal C style comment block), as long as you put a structural command inside the documentation block. Structural commands (like all other commands) start with a backslash (\\), or an at-sign (\@) in JavaDoc style, followed by a command name and one or more parameters. For instance, if you want to document the class \c Test in the example above, you could have also put the following documentation block somewhere in the input that is read by doxygen: \verbatim /*! \class Test \brief A test class. A more detailed class description. */ \endverbatim Here the special command \c \class is used to indicate that the comment block contains documentation for the class \c Test. Other structural commands are: See section \ref commands for detailed information about these and other commands. Note that the documentation block belonging to a file should always contain a structural command. To document a member of a C++ class, you must also document the class itself. The same holds for namespaces. To document a global C function, typedef, enum or preprocessor definition you must first document the file that contains it (usually this will be a header file, because that file contains the information that is exported to other source files). Let's repeat that, because it is often overlooked: to document global objects (functions, typedefs, enum, macros, etc), you must document the file in which they are defined. In other words, there must at least be a \verbatim /*! \file */ \endverbatim or a \verbatim /** @file */ \endverbatim line in this file. Here is an example of a C header named \c structcmd.h that is documented using structural commands: \verbinclude structcmd.h \htmlonly Click here for the corresponding HTML documentation that is generated by doxygen. \endhtmlonly \par Note: Because each comment block in the example above contains a structural command, all the comment blocks could be moved to another location or input file (the source file for instance), without affecting the generated documentation. The disadvantage of this approach is that prototypes are duplicated, so all changes have to be made twice! \subsection memberdoc Documenting compound members. If you want to document the members of a file, struct, union, class, or enum, and you want to put the documentation for these members inside the compound, it is sometimes desired to place the documentation block after the member instead of before. For this purpose doxygen has the following additional comment blocks: \verbatim /*!< ... */ \endverbatim This block can be used to put a Qt style documentation blocks after a member. The one line version look as follows: \verbatim //!< ... \endverbatim There are also JavaDoc versions: \verbatim /**< ... */ \endverbatim and \verbatim ///< ... \endverbatim Note that these blocks have the same structure and meaning as the special comment blocks above only the \< indicates that the member is located in front of the block instead of after the block. Here is an example of the use of these comment blocks: \verbinclude afterdoc.h \htmlonly Click here for the corresponding HTML documentation that is generated by doxygen. \endhtmlonly \warning These blocks can only be used to document \e members. They cannot be used to document files, classes, unions, structs, groups, namespaces and enums themselves. Furthermore, the structural commands mentioned in the previous section (like \\class) are ignored inside these comment blocks. \htmlonly Go to the next section or return to the index. \endhtmlonly */