=== Windows === 

If you use [http://en.wikipedia.org/wiki/Microsoft_Visual_Studio Microsoft Visual C++] (7.1 or later) compiler, you can build GEOS using [http://msdn.microsoft.com/en-us/library/dd9y37ha.aspx NMAKE] program and provided makefile.vc files:

{{{
autogen.bat
nmake /f makefile.vc MSVC_VER=1400
}}}

where 1400 is version number of Visual C++ compiler, here [http://en.wikipedia.org/wiki/Visual_C%2B%2B Visual C++ 8.0] from [http://msdn.microsoft.com/en-us/library/ms950416.aspx Visual Studio 2005] (supported versions are 1300, 1310, 1400 and 1500). The ''autogen.bat'' step is required to generate a couple of header files (''note:'' autogen.bat is available in SVN only).

In order to build debug configuration of GEOS, additional flag ''DEBUG=1'' is required:
{{{
nmake /f makefile.vc MSVC_VER=1400 DEBUG=1
}}}