/******************************************************************************

 *

 * 

 *

 * Copyright (C) 1997-2015 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 searching Searching

Doxygen indexes your source code in various ways to make it easier 

to navigate and find what you are looking for. 

There are also situations however where you want to

search for something by keyword rather than browse for it.

HTML browsers by default have no search capabilities that work across multiple

pages, so either doxygen or external tools need to help to facilitate 

this feature.

Doxygen has 7 different ways to add searching to the HTML output, each of which

has its own advantages and disadvantages:

1. Client side searching

   The easiest way to enable searching is to enable the built-in client

   side search engine. This engine is implemented using Javascript and DHTML

   only and runs entirely on the clients browser. So no additional tooling is

   required to make it work. 

   To enable it set 

   \ref cfg_searchengine "SEARCHENGINE" to \c YES in the config file

   and make sure \ref cfg_server_based_search "SERVER_BASED_SEARCH" is set

   to \c NO.

   An additional advantage of this method is that it provides live 

   searching, i.e. the search results are presented and adapted as you type.

   This method also has its drawbacks: it is limited to searching for symbols

   only. It does not provide full text search capabilities, and it does not

   scale well to very large projects (then searching becomes very slow).

2. Server side searching

   If you plan to put the HTML documentation on a web server, and that

   web server has the capability to process PHP code, then you can also use 

   doxygen's built-in server side search engine. 

   To enable this set both

   \ref cfg_searchengine "SEARCHENGINE" and 

   \ref cfg_server_based_search "SERVER_BASED_SEARCH" to \c YES in the config

   file and set \ref cfg_external_search "EXTERNAL_SEARCH" to \c NO.

   Advantages over the client side search engine are that it provides full

   text search and it scales well to medium side projects.

   Disadvantages are that it does not work locally (i.e. using a "file://" URL)

   and that it does not provide live search capabilities.

   @note In the future this option will probably be replaced by the next 

   search option.

3. Server side searching with external indexing

   With release 1.8.3 of doxygen, another server based search option has

   been added. With this option doxygen generates the raw data that can be 

   searched and leaves it up to external tools to do the indexing and 

   searching, meaning that you could use your own indexer and search engine 

   of choice. To make life easier doxygen ships with an example indexer 

   (doxyindexer) and search engine (doxysearch.cgi) based on 

   the Xapian open source search engine 

   library.

   To enable this search method set 

   \ref cfg_searchengine "SEARCHENGINE",

   \ref cfg_server_based_search "SERVER_BASED_SEARCH" and

   \ref cfg_external_search "EXTERNAL_SEARCH" all to \c YES.

   See \subpage extsearch for configuration details.

   Advantages over option 2 are that this method (potentially) scales to 

   very large projects. It is also possible to combine multiple doxygen 

   projects and external data into one search index. 

   The way the interaction with the search engine is done, makes it 

   possible to search from local HTML pages. Also the search results have 

   better ranking and show context information (if available).

   Disadvantages are that is requires a web server that can execute a CGI

   binary, and an additional indexing step after running doxygen.

4. Windows Compiled HTML Help

   If you are running doxygen on Windows, then you can make a 

   compiled HTML Help file (.chm) out of the HTML files produced by doxygen.

   This is a single file containing all HTML files and it also includes a

   search index. There are viewers for this format on many platforms,

   and Windows even supports it natively.

   To enable this set \ref cfg_generate_htmlhelp "GENERATE_HTMLHELP" to \c YES

   in the config file. To let doxygen compile the HTML Help file for you,

   you also need to specify the path to the HTML compiler (hhc.exe) using the

   \ref cfg_hhc_location "HHC_LOCATION" config option and the name of the

   resulting CHM file using \ref cfg_chm_file "CHM_FILE".

   An advantage of this method is that the result is a single file that can

   easily be distributed. It also provides full text search. 

   Disadvantages are that compiling the CHM file only works on Windows

   and requires Microsoft's HTML compiler, which is not very actively supported

   by Microsoft. Although the tool works fine for most people, it can 

   sometimes crash for no apparent reason (how typical). 

5. Mac OS X Doc Sets
 

   If you are running doxygen on Mac OS X 10.5 or higher, 

   then you can make a "doc set" out of the HTML files produced by doxygen.

   A doc set consists of a single directory with a special structure 

   containing the HTML files along with a precompiled search index. 

   A doc set can be embedded in Xcode (the integrated development environment 

   provided by Apple).

   To enable the creation of doc sets set \ref cfg_generate_docset "GENERATE_DOCSET"

   to \c YES in the config file. There are a couple of other doc set related

   options you may want to set. After doxygen has finished you will find

   a Makefile in the HTML output directory. Running "make install" on this

   Makefile will compile and install the doc set.

   See this 

   article for more info.

   Advantage of this method is that it nicely integrates with the Xcode

   development environment, allowing for instance to click on an identifier 

   in the editor and jump to the corresponding section in the doxygen 

   documentation.

   Disadvantage is that it only works in combination with Xcode on MacOSX.

6. Qt Compressed Help
 

   If you develop for or want to install the Qt application framework,

   you will get an application 

   called Qt assistant. 

   This is a help viewer for Qt Compressed Help files (.qch).

   To enable this feature set \ref cfg_generate_qhp "GENERATE_QHP" to \c YES.

   You also need to fill in the other Qt help related options, such as

   \ref cfg_qhp_namespace "QHP_NAMESPACE", 

   \ref cfg_qhg_location "QHG_LOCATION", 

   \ref cfg_qhp_virtual_folder "QHP_VIRTUAL_FOLDER".

   See this article 

   for more info.

   Feature wise the Qt compressed help feature is comparable with the CHM 

   output, with the additional advantage that compiling the QCH file is 

   not limited to Windows.

   Disadvantage is that it requires setting up a Qt 4.5 (or better) for

   each user, or distributing the Qt help assistant along with 

   the documentation, which is complicated by the fact that it is not

   available as a separate package at this moment.

7. Eclipse Help Plugin

   If you use eclipse, you can embed the documentation generated by

   doxygen as a help plugin. It will then appear as a topic in the help 

   browser that can be started from "Help contents" in the Help menu.

   Eclipse will generate a search index for the documentation when you

   first search for a keyword.

   To enable the help plugin set 

   \ref cfg_generate_eclipsehelp "GENERATE_ECLIPSEHELP" to \c YES,

   and define a unique identifier for your project via

   \ref cfg_eclipse_doc_id "ECLIPSE_DOC_ID", i.e.:

\verbatim

   GENERATE_ECLIPSEHELP = YES

   ECLIPSE_DOC_ID       = com.yourcompany.yourproject

\endverbatim

   then create the \c com.yourcompany.yourproject directory (so with

   the same name as the value of \c ECLIPSE_DOC_ID) in the 

   \c plugin directory of eclipse and after doxygen completes copy

   to contents of the help output directory to 

   the \c com.yourcompany.yourproject directory.

   Then restart eclipse to make let it find the new plugin.

   The eclipse help plugin provides similar functionality as the

   Qt compressed help or CHM output, but it does require that Eclipse is

   installed and running.

\htmlonly

Go to the next section or return to the

 index.

\endhtmlonly

*/