/******************************************************************************
*
*
*
* Copyright (C) 1997-2000 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.
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/*! \page docblocks Documenting the code
\subsection specialblock Special documentation blocks
The following types of special documentation blocks are supported by doxygen:
- The Qt style, where special documentation blocks look like:
\verbatim
/*!
... text ...
*/
\endverbatim and the one line version:
\verbatim
//! ... one line of text ...
\endverbatim
- The JavaDoc style, where special documentation blocks look like:
\verbatim
/**
* ... text ...
*/
\endverbatim and the one line version:
\verbatim
/// ... one line of text ...
\endverbatim
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 detail 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.
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 are also the first
sentence of the detailed description
(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.
Here is the same piece of code, this time documented using the JavaDoc
style:
\verbinclude jdstyle.cpp
\htmlonly
Click here
for the corresponding HTML documentation that is generated by doxygen.
\endhtmlonly
Note that by default the first sentence of the documentation (until the .)
is treated as a brief description, whereas the documentation block as a whole
forms the detailed description. If you want to put a dot in the middle of a
sentence you should put a backslash and space behind it. Example:
\verbatim
/** Brief description (e.g.\ using only a few words). Details follow. */
\endverbatim
The brief description is required for the JavaDoc style, unless you set
\ref cfg_javadoc_autobrief "JAVADOC_AUTOBRIEF" to NO. If you do this,
doxygen treats JavaDoc comments just like Qt comments (i.e. You have
to insert an explicit \ref cmdbrief "\\brief" command to add a brief description).
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
(assuming you use the Qt style comments).
\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
(\\) 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 indicated that the
comment block contains documentation for the class \c Test.
Other structural commands are:
- \c \struct to document a C-struct.
- \c \union to document a union.
- \c \enum to document an enumeration type.
- \c \fn to document a function.
- \c \var to document a variable or typedef or enum value.
- \c \def to document a \#define.
- \c \file to document a file.
- \c \namespace to document a namespace.
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 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).
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 a 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. 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
*/