NcML refers to the NetCDF meta-language, which is a markup language for creating and modifying virtual datasets. The netcdfx library makes it possible to read, from Fortran, NetCDF aggregates defined by NcML. Essentially, the netcdfx library is a wrapper for NetCDF which allows one to read a NcML file as if it were a NetCDF file.
This library depends on the FoX library for reading and parsing XML from Fortran.
I originally wrote this software to accomodate custom "branches" of data to be accessible with the RADS software, but it was superceded by the now-native capability of RADS to do this same thing.