--- On unix:

ruby extconf.rb

make

make install

--- On Windows, the complete installer version:

double click install-on-windows.rb

--- On Windows, source only:

Set up Microsoft Visual C (I use 6) for commandline compiling with vcvars32.bat

Edit vcvars32.bat to point to a user include and lib directory, which you create.

Put the development versions of the support libraries (SDL, SDL_ttf, smpeg, etc) in the lib and include directories. .h files go in the include dir, others, mostly .lib files, in the lib dir. DLL's should be put in RUDL's dll dir.

Continue as "On unix"

--- Windows environment variables example:

With Visual Studio in D:\Program Files\VStudio\, 
and the include and lib dirs beneath the RUDL dir: d:\rubyspul\rudl\.

vvv
include=D:\Program Files\VStudio\VC98\Include;d:\rubyspul\rudl\include

lib=D:\Program Files\VStudio\VC98\Lib;d:\rubyspul\rudl\lib

MSDevDir=D:\Program Files\VStudio\Common\MSDev98

Path=D:\Program Files\VStudio\Common\MSDev98\BIN;D:\Program Files\VStudio\VC98\BIN;D:\Program Files\VStudio\Common\MSDev98\TOOLS
^^^