Research
Common API for HDF4 and HDF5
It is clear that HDF4 files will be around for a long time. At the same time, many applications are migrating from HDF4 to HDF5. These applications, which often need to support HDF4 and HDF5 for essentially the same operations, may benefit substantially from a common API to both HDF4 and HDF5. Because HDF4 and HDF5 are not exactly the same, the API would have to be able to deal meaningfully with those objects are not in the intersection of the two. A "Java object package" exists that does this for HDFView. What is needed is a library for C and Fortran.
Merging_H4_and_H5-ideas from 1997.doc; Also web page about Java Object Package: https://support.hdfgroup.org/products/java/hdf-java-html/hdf-object/index.html