/**
  
  @page external_code External Code using OpenMS
  
	If %OpenMS' TOPP and UTILS tools are not enough in a certain scenario, you can either
	request a change to %OpenMS, if you feel this functionality is useful for others as well,
	or modify/extend %OpenMS privately.
	For the latter, there are multiple ways to do this: You can modify the developer version of %OpenMS by changing
	existing tools or adding new ones. Or you use an <b>External Project</b> to write a new tool, while not touching
	%OpenMS itself (see below on how to do that).
	Once you've finished your new tool, and it only needs to run on the development machine, you're done.
	If you want to ship it to a new client machine, see @ref development_external_ship .
	
	@section development_external Compiling external code
	
	It is very easy to set up an environment to write your own programs using %OpenMS. Make sure you downloaded and installed the source package of %OpenMS/TOPP properly.
	Note that you cannot use the 'install' target when working with the development version of %OpenMS - it must be built and used within the build tree.
	<br>
	<br>
	
	All important compiler settings and preprocessor definitions along with the %OpenMS library will
	be available to you.
	The most important variables are:
	<UL>
	<LI>OpenMS_INCLUDE_DIRECTORIES - all include directories containing %OpenMS headers
	<LI>OPENMS_ADDCXX_FLAGS - preprocessor macros we require written as (-DMACRO1 -DMACRO2) etc
	</UL>
	and the %OpenMS target itself (which you can link against).
	<br>	
	The example that follows will be explained in details:

\include examples/external_code/CMakeLists.txt

	The command @em project defines the name of the project - the name is only of interest of you're working in an IDE or want to export this project's targets.
	To compile your program just append it to the @em my_executables list. If you also use object files (classes which do not contain a main program), append them to the @em my_sources list. In the next step CMake creates a statically linked library of the object files, listed in @em my_sources.
	This simple CMakeLists.txt example can be extended to also build shared libraries, include other external libraries and so on.

	An example external project can be found in @em OpenMS/share/OpenMS/examples/external_code.
	Copy these files to a separate directory and use CMake to configure it (here as an in-source build).
@code
cd <path_to_external_project>
cmake -G "<generator>" .
@endcode
	
	For more information visit the website of cmake at cmake.org and consult the documentation.
	<br>
	<b>Have fun coding with %OpenMS!</b>

@section development_external_ship Shipping your external code to a new machine

  If you've modified %OpenMS itself and not used an external project you can just use our installer scripts,
	to build your own %OpenMS installer for your platform (see our internal FAQ which is built using "make doc_internal") and ship that to a client machine.
	
	If you've used an external project and have a new executable (+ an optional new library), you can use the 
	installer approach as well, and manually copy the new executable to the TOPP/UTILS binary directory (e.g. on
	Windows this could be @em c:/program files/OpenMS/bin, on Linux it could be @em /bin.
	
	If you do NOT use the installer, you can copy all required files manually, plus a few extra steps - see below.
	What needs to be done is a little platform dependent, thus very cumbersome to explain. You should
	look at the cmake installer scripts, to see whats required (for Mac and Linux see @em %OpenMS/cmake/package*.cmake, for
	Windows see @em https://github.com/OpenMS/windows-installer/OpenMS_installer.nsi ).
	<br>
	In short:
	<ul>
	<li>copy the %OpenMS/share/%OpenMS directory to the client machine (e.g. <client/my_dir>/share) and set the environment variable @em OPENMS_DATA_PATH to this directory
	<li>copy the %OpenMS library (%OpenMS.dll for Windows or %OpenMS.so/.dylib for Linux/Mac) to <client/my_dir>/bin
	<li>copy all Qt4 libraries to the client <client/my_dir>/bin or on Linux/Mac make sure you have installed the Qt4 package
	<li>[Windows only] copy Xerces dll (see contrib/lib) to <client/my_dir>/bin
	<li>[Windows only] install the VS redistributable package (see Microsoft Homepage) on the client machine which corresponds to the VS version 
		  that was used to compile your code (use the correct redistributable package! , i.e. architecture 32|64bit, VS version, VS Service Pack	version).
			If you choose the wrong redistributable package, you will get "Application failed to initialize properly..." error messages.
	</ul>
	
	


*/
