This .zip archive contains DLL libraries and the associated header (.h)
and module-definition (.def) files of FFTW compiled for Win32.  It
also contains the corresponding bench.exe test/benchmark programs
and wisdom utilities.

There are three libraries: single precision (float), double precision,
and extended precision (long double).  To use the third library,
your compiler must have sizeof(long double) == 12.

In order to link to these .dll files from Visual C++, you need to
create .lib "import libraries" for them, and can do so with the "lib"
command that comes with VC++.  In particular, run:
     lib /def:libfftw3f-3.def
     lib /def:libfftw3-3.def
     lib /def:libfftw3l-3.def

The single- and double-precision libraries use SSE and SSE2, respectively,
but should also work on older processors (the library checks at runtime
to see whether SSE/SSE2 is supported and disables the relevant code if not).

They were compiled by the GNU C compiler for MinGW, specifically:
i686-w64-mingw32-gcc (GCC) 4.9.1