Created hdf5 files, but want netcdf4 files

Using matlab version 8.1.0.604 (R2013a), I have tried to create netcdf4 files using nccreate & netcdf.create. But the unix file command says they are hdf5 files. (And this creates a problem when trying to port them to an OPeNDaP server which will not serve hdf5 files.)

Also, I am not clear on the difference between nccreate and netcdf.create. See code fragments:

1) nccreate(filename, 'netcdf4')

>> nccreate('myfile_nccreate_netcdf4.nc','netcdf4')

>> !file myfile_nccreate_netcdf4.nc

myfile_nccreate_netcdf4.nc: Hierarchical Data Format (version 5) data

2) nccreate(filename, 'netcdf4_classic')

>> nccreate('myfile_nccreate_netcdf4_classic.nc','netcdf4_classic')

>> !file myfile_nccreate_netcdf4_classic.nc

myfile_nccreate_netcdf4_classic.nc: Hierarchical Data Format (version 5) data

3) netcdf.create(filename, 'netcdf4')

>> ncid=netcdf.create('myfile_netcdf.create_netcdf4','netcdf4');

>> netcdf.close(ncid)

>> !file myfile_netcdf.create_netcdf4

myfile_netcdf.create_netcdf4: Hierarchical Data Format (version 5) data