Build in the usual way: perl Makefile.PL make test make install For that to work, you'll need a compiler that provides support for the _Decimal64 type. My (mingw64.sf) ports of gcc-4.6.3 and gcc-4.7.0 provided such support, but my (mingw.org) port of gcc-4.5.2 did not. If your compiler provides the strtod64 function and you want to make use of it, either provide the Makefile.PL with the command line argument STRTOD64=1, or edit the Makefile.PL to set $strtod64 to 1. Consider this module to be alpha software. Cheers, Rob