NetCDF Library: Memory management during file creation

I am using NetCDF capabilities of the R2013a version (under Microsoft XP).

I am wondering how is the memory managed during a NetCDF file creation:

Between the instructions:

fCdf = netcdf.create(ncPathFileName, 'NC_CLOBBER'); and netcdf.close(fCdf);

the memory used by matlab is increasing (I guess to store the data to be saved in the NetCDF file); However it seems that this memory is not automatically released after the netcdf.close.

Where are stored the data pointed by ncid (fCdf variable in my example) and how to clear them? Must we add a "clear functions" instruction after each "netcdf.close"?

Regards