The UDUNITS package supports units of physical quantities. Its C library provides for arithmetic manipulation of units and for conversion of numeric values between compatible units. The package contains an extensive unit database, which is in XML format and user-extendable. The package also contains a command-line utility for investigating units and converting values.
Didn't find a solution in the version-specific UDUNITS documentation? Try the following:
Training for the UDUNITS package is not currently offered.