The mfhdf library was designed to be completely transparent to the programmer. HDF supports a "multi-file" SDS interface and the complete netCDF interface as defined by Unidata netCDF Release 2.3.2. (Please note that HDF4 cannot read NetCDF 64-bit files.

Using either interface, you are able to read XDR-based netCDF files, HDF-based netCDF files and pre-HDF4.x HDF files. The library determines what type of file is being accessed and handles it appropriately. Any of the above types of files may be modified. However, the library will only create new files based on HDF (you can't create new XDR-based netCDF files).

Summary of HDF and XDR file interoperability for the HDF and netCDF application interfaces:

 

 Files created by
DFSD interface
Files created by
SD interface
Files written by
NC interface
 HDFHDFHDFUnidata netCDF
Accessed by DFSDYesYesYesNo
Accessed by SDYesYesYesYes
Accessed by NCYesYesYesYes

For more information, you can refer to the section entitled HDF Interface vs. netCDF Interface in the SD chapter of the User's Guide.