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 _Decimal128 type. If your compiler provides the strtod128 function and you want to make use of it, either provide the Makefile.PL with the command line argument STRTOD128=1, or edit the Makefile.PL to set $strtod128 to 1. Cheers, Rob