/******************************************************************************
 *
 * $Id$
 *
 * Copyright (C) 1997-1999 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.
 *
 * All output generated with Doxygen is not covered by this license.
 *
 */
/*! \page config

\section config Configuration

\subsection config_format Format

A configuration file is a free-form ASCII text file with a structure that
is similar to that of a Makefile. It is parsed by a 
recursive-descent parser that is built into \c doxygen.
The file may contain tabs and newlines for formatting purposes.
The statements in the file are case-sensitive.
Comments may be placed anywhere within the file (except within quotes).
Comments begin with the \c # character and end at the end of the 
line.

The file essentially consists of a list of assignment statements.
Each statement consists of a \c TAG_NAME written in capitals,
followed by the \c = character and one or more values.
Values are sequences of non-blanks. If the value should contain one or more
blanks it must be surrounded by quotes ("...").
Multiple lines can be concatenated by inserting a backslash (\\)
as the last character of a line.
Environment variables can expanded using the pattern \$(ENV_VARIABLE_NAME).

The configuration options can be divided into several categories.
Below is a list of tags that are recognized for each category.

\subsection config_general General options
<dl>

<dt>\c PROJECT_NAME <dd>
 \addindex PROJECT_NAME
 The \c PROJECT_NAME tag is a single word (or a sequence of words
 surrounded by double-quotes) that should identify the project for which the 
 documentation is generated. This name is used in the title of most 
 generated pages and in a few other places.

<dt>\c PROJECT_NUMBER <dd>
 \addindex PROJECT_NUMBER
 The \c PROJECT_NUMBER tag can be used to enter a project or revision number.
 This could be handy for archiving the generated documentation or
 if some version control system is used.

<dt>\c OUTPUT_DIRECTORY <dd> 
 \addindex OUTPUT_DIRECTORY
 The \c OUTPUT_DIRECTORY tag is used to specify the (relative or absolute) 
 path into which the generated HTML and Latex documentation will be written. 
 If a relative path is entered, it will be relative to the location 
 where doxygen was started. If left blank the current directory will be used.

<dt>\c QUIET <dd>
 \addindex QUIET
 The \c QUIET tag can be used to turn on/off the messages that are generated
 to standard output by doxygen. Possible values are \c YES and \c NO, 
 where \c YES implies that the messages are off.
 If left blank \c NO is used.

<dt>\c WARNINGS <dd>
 \addindex WARNINGS
 The \c WARNINGS tag can be used to turn on/off the warning messages that are
 generated to standard error by doxygen. Possible values are \c YES and \c NO, 
 where \c YES implies that the warnings are on. If left blank \c NO is used.

 \b Tip: Turn warnings on while writing the documentation.

<dt>\c DISABLE_INDEX <dd>
 \addindex DISABLE_INDEX
 If you want full control over the layout of the generated HTML pages it
 might be necessary to disable the index and replace it with your own.
 The DISABLE_INDEX tag can be used to turn on/off the condensed index at
 top of each page. A value of NO (the default) enables the index and the
 value YES disables it.

<dt>\c EXTRACT_ALL <dd>
 \addindex EXTRACT_ALL
 If the \c EXTRACT_ALL tag is set to \c YES all classes and functions will be
 included in the documentation, even if no documentation was available.

 \b Notice: This will also disable the warnings about undocumented members 
 that are normally produced when \c WARNINGS is set to \c YES

<dt>\c EXTRACT_PRIVATE <dd>
 \addindex EXTRACT_PRIVATE
 If the \c EXTRACT_PRIVATE tag is set to \c YES all
 documentation for private members will be extracted as well.

<dt>\c HIDE_UNDOC_MEMBERS <dd>
 \addindex HIDE_UNDOC_MEMBERS
 If the \c HIDE_UNDOC_MEMBERS tag is set to \c YES, Doxygen will hide all
 undocumented members inside documented classes or files. 
 If set to \c NO (the default) these members will be included in the
 various overviews, but no documentation section is generated.

<dt>\c HIDE_UNDOC_CLASSES <dd>
 \addindex HIDE_UNDOC_CLASSES
 If the \c HIDE_UNDOC_CLASSESS tag is set to \c YES, Doxygen will hide all
 undocumented classes.
 If set to \c NO (the default) these classes will be included in the
 various overviews.

<dt>\c BRIEF_MEMBER_DESC <dd>
 \addindex BRIEF_MEMBER_DESC
 If the \c BRIEF_MEMBER_DESC tag is set to \c YES (the default) Doxygen will
 include brief member descriptions after the members that are listed in
 the file and class documentation (similar to JavaDoc).
 Set to NO to disable this.

<dt>\c INTERNAL_DOCS <dd>
 \addindex INTERNAL_DOCS
 The \c INTERNAL_DOCS tag determines if documentation
 that is typed after a \\internal command is included. If the tag is set
 to \c NO (the default) then the documentation will be excluded.
 Set it to \c YES to include the internal documentation.

<dt>\c REPEAT_BRIEF <dd>
 \addindex REPEAT_BRIEF
 If the \c REPEAT_BRIEF tag is set to \c YES (the default) Doxygen will 
 prepend the brief description of a member or function before the detailed 
 description 

 \par Notice: 
 If both \c HIDE_UNDOC_MEMBERS and \c BRIEF_MEMBER_DESC are set to \c NO, the 
 brief descriptions will be completely suppressed.

<dt>\c FULL_PATH_NAMES <dd>
 \addindex FULL_PATH_NAMES
 If the \c FULL_PATH_NAMES tag is set to \c YES Doxygen will prepend the full
 path before files name in the file list and in the header files. If set
 to NO the shortest path that makes the file name unique will be used

<dt>\c STRIP_FROM_PATH <dd>
 \addindex STRIP_FROM_PATH
 If the \c FULL_PATH_NAMES tag is set to \c YES then the \c STRIP_FROM_PATH tag
 can be used to strip a user defined part of the path. Stripping is
 only done if the specified string matches the left-hand part of the 
 path.

<dt>\c CLASS_DIAGRAMS <dd>
 \addindex CLASS_DIAGRAMS
 If the \c CLASS_DIAGRAMS tag is set to \c YES (the default) Doxygen will
 generate a class diagram (in Html and LaTeX) for classes with base or
 super classes. Setting the tag to \c NO turns the diagrams off.

<dt>\c CASE_SENSE_NAMES <dd>
 \addindex CASE_SENSE_NAMES
 If the \c CASE_SENSE_NAMES tag is set to \c NO (the default) then Doxygen
 will only generate file names in lower case letters. If set to
 \c YES upper case letters are also allowed. This is useful if you have
 classes or files whose names only differ in case and if your file system
 supports case sensitive file names.

<dt>\c VERBATIM_HEADERS <dd>
 \addindex VERBATIM_HEADERS
  If the VERBATIM_HEADERS tag is set the YES (the default) then Doxygen\n";
  will generate a verbatim copy of the header file for each class for\n";
  which an include is specified. Set to NO to disable this.\n";
  \sa Section \ref cmdclass.

</dl>

\subsection config_input Input related options
<dl>

<dt>\c INPUT <dd>
 \addindex INPUT
 The \c INPUT tag is used to specify the files and/or directories that contain 
 documented source files. You may enter file names like 
 \c myfile.cpp or directories like \c /usr/src/myproject. 
 Separate the files or directories with spaces.<br>

 \b Notice: This tag (and only this tag) is \e required.

<dt>\c FILE_PATTERNS <dd>
 \addindex FILE_PATTERNS
 If the value of the \c INPUT tag contains directories, you can use the 
 \c FILE_PATTERNS tag to specify one or more wildcard patterns 
 (like \c *.cpp and \c *.h ) to filter out the source-files 
 in the directories. If left blank all files are included 
 (i.e. wildcard <tt>*</tt>).

<dt>\c RECURSIVE <dd>
 \addindex RECURSIVE
 The \c RECURSIVE tag can be used to specify whether or not subdirectories
 should be searched for input files as well. Possible values are \c YES 
 and \c NO.  If left blank \c NO is used.

<dt>\c EXCLUDE <dd>
 \addindex EXCLUDE
 The \c EXCLUDE tag can be used to specify files and/or directories that should
 excluded from the \c INPUT source files. This way you can easily exclude a
 subdirectory from a directory tree whose root is specified with the \c INPUT tag.

<dt>\c EXCLUDE_PATTERNS <dd>
 \addindex EXCLUDE_PATTERNS
 If the value of the INPUT tag contains directories, you can use the
 \c EXCLUDE_PATTERNS tag to specify one or more wildcard patterns to exclude
 certain files from those directories.


<dt>\c EXAMPLE_PATH <dd>
 \addindex EXAMPLE_PATH
 The \c EXAMPLE_PATH tag can be used to specify one or more files or
 directories that contain example code fragments that are included (see
 the \\include command in section \ref cmdinclude).

<dt>\c INCLUDE_PATH <dd>
 \addindex INCLUDE_PATH
 The INCLUDE_PATH tag can be used to specify one or more directories that
 contain include files that are not input files but should be processed by
 the preprocessor.
 
<dt>\c INPUT_FILTER <dd>
 \addindex INPUT_FILTER
 The \c INPUT_FILTER tag can be used to specify a program that doxygen should
 invoke to filter for each input file. Doxygen will invoke the filter program
 by executing (via popen()) the command:
\verbatim <filter> <input-file>
\endverbatim
 
 where \<filter\>
 is the value of the \c INPUT_FILTER tag, and \<input-file\> is the name of an
 input file. Doxygen will then use the output that the filter program writes
 to standard output.

</dl>

\subsection html_output HTML related options
<dl>

<dt>\c GENERATE_HTML <dd>
 \addindex GENERATE_HTML
 If the \c GENERATE_HTML tag is set to \c YES (the default) Doxygen will
 generate HTML output

<dt>\c HTML_OUTPUT <dd>
 \addindex HTML_OUTPUT
 The \c HTML_OUTPUT tag is used to specify where the HTML docs will be put.
 If a relative path is entered the value of \c OUTPUT_DIRECTORY will be
 put in front of it. If left blank `html' will be used as the default path.

<dt>\c HTML_HEADER <dd>      
 \addindex HTML_HEADER
 The \c HTML_HEADER tag can be used to specify a user defined HTML 
 header file for each generated HTML page. To get valid HTML the header file
 should contain at least a \c <HTML> and a \c <BODY> tag. Example:
\verbatim
  <HTML>
    <HEAD>
      <TITLE>My title</TITLE>
    </HEAD>
    <BODY BGCOLOR="#FFFFFF">
\endverbatim
 If the tag is left blank doxygen will generate a 
 standard header. 
   
<dt>\c HTML_FOOTER <dd>
 \addindex HTML_FOOTER
 The \c HTML_FOOTER tag can be used to specify a user defined HTML footer for 
 each generated HTML page. To get valid HTML the header file should contain
 at least a \c </BODY> and a \c </HTML> tag.  Example:
\verbatim
    </BODY>
  </HTML>
\endverbatim
 If the tag is left blank doxygen will generate a standard footer.

</dl>

\subsection latex_output LaTeX related options
<dl>

<dt>\c GENERATE_LATEX <dd>
 \addindex GENERATE_LATEX
 If the \c GENERATE_LATEX tag is set to \c YES (the default) Doxygen will
 generate Latex output.

<dt>\c LATEX_OUTPUT <dd>
 \addindex LATEX_OUTPUT
 The \c LATEX_OUTPUT tag is used to specify where the LaTeX docs will be put.
 If a relative path is entered the value of \c OUTPUT_DIRECTORY will be
 put in front of it. If left blank `latex' will be used as the default path.

<dt>\c COMPACT_LATEX <dd>
 \addindex COMPACT_LATEX
 If the \c COMPACT_LATEX tag is set to \c YES Doxygen generates more compact
 LaTeX documents. This may be useful for small projects and may help to
 save some trees in general.

<dt>\c PAPER_TYPE <dd>
 \addindex PAPER_TYPE
 The PAPER_TYPE tag can be used to set the paper type that is used
 by the printer. Possible values are: 
 <ul>
 <li><code>a4</code> (210 x 297 mm).
 <li><code>a4wide</code> (same as a4, but including the a4wide package).
 <li><code>letter</code> (8.5 x 11 inches).
 <li><code>legal</code> (8.5 x 14 inches).
 <li><code>executive</code> (7.25 x 10.5 inches)
 </ul> 
 If left blank a4wide will be used.

<dt>\c EXTRA_PACKAGES <dd>
 \addindex EXTRA_PACKAGES
 The EXTRA_PACKAGES tag can be used to specify one or more LaTeX 
 package names that should be included in the LaTeX output.
 To get the times font for instance you can specify 
\verbatim
EXTRA_PACKAGES = times
\endverbatim
 If left blank no extra packages will be included.
</dl>

\subsection man_output Man page related options
<dl>

<dt>\c GENERATE_MAN <dd>
 \addindex GENERATE_MAN
 If the \c GENERATE_MAN tag is set to \c YES (the default) Doxygen will
 generate man pages for classes and files.

<dt>\c MAN_OUTPUT <dd>
 \addindex MAN_OUTPUT
 The \c MAN_OUTPUT tag is used to specify where the man pages will be put.
 If a relative path is entered the value of \c OUTPUT_DIRECTORY will be
 put in front of it. If left blank `man' will be used as the default path.
 A directory man3 will be created inside the directory specified by 
 \c MAN_OUTPUT.

</dl>

\subsection config_prepro Preprocessor related options
<dl>

<dt>\c ENABLE_PREPROCESSING <dd>
 \addindex ENABLE_PREPROCESSING
 If the \c ENABLE_PREPROCESSING tag is set to \c YES (the default) Doxygen will
 evaluate all C-preprocessor directives found in the sources and include
 files. 

<dt>\c MACRO_EXPANSION <dd>
 \addindex MACRO_EXPANSION
 If the \c MACRO_EXPANSION tag is set to \c YES Doxygen will expand all macro
 names in the source code. If set to \c NO (the default) only conditional 
 compilation will be performed.

<dt>\c SEARCH_INCLUDES <dd>
 \addindex SEARCH_INCLUDES 
 If the \c SEARCH_INCLUDES tag is set to \c YES (the default) the includes files
 in the \c INCLUDE_PATH (see below) will be search if a \#include is found.

<dt>\c INCLUDE_PATH <dd>
 \addindex INCLUDE_PATH
 The \c INCLUDE_PATH tag can be used to specify one or more directories that
 contain include files that are not input files but should be processed by
 the preprocessor.

<dt>\c PREDEFINED <dd>
 \addindex PREDEFINED
 The \c PREDEFINED tag can be used to specify one or more macro names that
 are defined before the preprocessor is started (similar to the -D option of
 gcc). The argument of the tag is a list of macros of the form:
 <code>name</code> or <code>name=definition</code> (no spaces). 
 If the definition and the = are omitted =1 is assumed.

<dt>\c EXPAND_ONLY_PREDEF <dd>
 \addindex EXPAND_ONLY_PREDEF
 If the \c EXPAND_ONLY_PREDEF and \c MACRO_EXPANSION tags are both set to YES
 then the macro expansion is limited to the macros specified with the
 \c PREDEFINED tag.

</dl>

\subsection config_extref External reference options
<dl>

<dt>\c TAGFILES <dd> 
 \addindex TAGFILES
 The \c TAGFILES tag can be used to specify one or more tagfiles. 
 See section \ref doxytag_usage for more information about the usage of 
 tag files.
 
 \par Notice:
  Each tag file most have a unique name and if a tag file is not located
  in the directory in which doxygen is run, you must also specify the
  path to the tagfile here.

<dt>\c GENERATE_TAGFILE <dd>
 \addindex GENERATE_TAGFILE
 When a file name is specified after \c GENERATE_TAGFILE, doxygen will create
 a tag file that is based on the input files it reads.
 See section \ref doxytag_usage for more information about the usage of 
 tag files.

<dt>\c ALLEXTERNALS <dd>
 \addindex ALLEXTERNALS
 if the \c ALLEXTERNALS tag is set to \c YES all external class will be listed
 in the class index. If set to \c NO only the inherited external classes
 will be listed.

<dt>\c PERL_PATH <dd>
 \addindex PERL_PATH
 The \c PERL_PATH should be the absolute path and name of the perl script
 interpreter (i.e. the result of `<tt>which perl</tt>').

</dl>
\subsection config_search Search engine options
<dl>

<dt>\c SEARCHENGINE <dd>
 \addindex SEARCHENGINE
 The \c SEARCHENGINE tag specifies whether or not a 
 search should be used. Possible values are \c YES and \c NO. 
 If set to \c NO or left blank, the values of all other tags in this section 
 will be ignored.

<dt>\c CGI_NAME <dd>
 \addindex CGI_NAME
 The \c CGI_NAME tag should be the name of the CGI script that
 starts the search engine (<tt>doxysearch</tt>) with the correct parameters.
 A script with this name will be generated by doxygen.

<dt>\c CGI_URL <dd>
 \addindex CGI_URL
 The \c CGI_URL tag should be the absolute URL to the directory where the
 cgi binaries are located. See the documentation of your http daemon for 
 details.

<dt>\c DOC_URL <dd>
 \addindex DOC_URL
 The \c DOC_URL tag should be the absolute URL to the directory where the
 documentation is located. If left blank the absolute path to the 
 documentation, with <tt>file://</tt> prepended to it, will be used. 
 This is correct for local viewing only.

<dt>\c DOC_ABSPATH <dd>
 \addindex DOC_ABSPATH
 The \c DOC_ABSPATH tag should be the absolute path to the directory where the
 documentation is located. If left blank the directory on the local machine
 will be used.

<dt>\c BIN_ABSPATH <dd>     
 \addindex BIN_ABSPATH
 The \c BIN_ABSPATH tag must point to the directory where the doxysearch binary
 is installed.

<dt>\c EXT_DOC_PATHS <dd>  
 \addindex EXT_DOC_PATHS
 The \c EXT_DOC_PATHS tag can be used to specify one or more paths to 
 documentation generated for other projects. This allows doxysearch to search
 the documentation for these projects as well. All paths must be absolute.

</dl>
<h2>Examples</h2>

Suppose you have a simple project consisting of two files: a source file 
\c example.cc and a header file \c example.h.
Then a minimal configuration file is as simple as:
\verbatim
INPUT            = example.cc example.h
\endverbatim

Assuming the example makes use of Qt classes and perl is located 
in <code>/usr/bin</code>, a more realistic configuration file would be:
\verbatim
PROJECT_NAME     = Example
INPUT            = example.cc example.h
WARNINGS         = YES
TAGFILES         = qt.tag
PERL_PATH        = /usr/bin/perl
SEARCHENGINE     = NO
\endverbatim

To generate the documentation for the 
<a href="http://www.stack.nl/~dimitri/qdbttabular/index.html">QdbtTabular</a> package
I have used the following configuration file:
\verbatim
PROJECT_NAME     = QdbtTabular
OUTPUT_DIRECTORY = html
WARNINGS         = YES
INPUT            = examples/examples.doc src
FILE_PATTERNS    = *.cc *.h
INCLUDE_PATH     = examples
TAGFILES         = qt.tag
PERL_PATH        = /usr/local/bin/perl
SEARCHENGINE     = YES
CGI_NAME         = search.cgi
CGI_URL          = http://www.stack.nl/~dimitri/cgi-bin
DOC_URL          = http://www.stack.nl/~dimitri/qdbttabular
DOC_ABSPATH      = /home/dimitri/.html/qdbttabular
BIN_ABSPATH      = /home/dimitri/bin
\endverbatim

To regenerate the Qt documentation from the sources, you could use the
following config file:
\verbatim
PROJECT_NAME         = Qt
OUTPUT_DIRECTORY     = qt_docs
HIDE_UNDOC_MEMBERS   = YES
HIDE_UNDOC_CLASSES   = YES
ENABLE_PREPROCESSING = YES
MACRO_EXPANSION      = YES
EXPAND_ONLY_PREDEF   = YES
SEARCH_INCLUDES      = YES
FULL_PATH_NAMES      = YES
STRIP_FROM_PATH      = $(QTDIR)/
PREDEFINED           = USE_TEMPLATECLASS Q_EXPORT= \
                       QArrayT=QArray \
                       QListT=QList \
                       QDictT=QDict \
                       QQueueT=QQueue \
                       QVectorT=QVector \
                       QPtrDictT=QPtrDict \
                       QIntDictT=QIntDict \
                       QStackT=QStack \
                       QDictIteratorT=QDictIterator \
                       QListIteratorT=QListIterator \
                       QCacheT=QCache \
                       QCacheIteratorT=QCacheIterator \
                       QIntCacheT=QIntCache \
                       QIntCacheIteratorT=QIntCacheIterator \
                       QIntDictIteratorT=QIntDictIterator \
                       QPtrDictIteratorT=QPtrDictIterator
INPUT                = $(QTDIR)/doc \
                       $(QTDIR)/src/widgets \
                       $(QTDIR)/src/kernel \
                       $(QTDIR)/src/dialogs \
                       $(QTDIR)/src/tools
FILE_PATTERNS        = *.cpp *.h q*.doc
INCLUDE_PATH         = $(QTDIR)/include 
RECURSIVE            = YES
\endverbatim

Here Doxygen's preprocessor is used to substitute some
macro names that are normally substituted by the C preprocessor,
but without doing full macro expansion.

*/