NCDF_ATTNAME function returns the name of an
attribute in a netCDF file given its ID. The NULL string ("") is returned if there is no such attribute.
Result = NCDF_ATTNAME(
Cdfid, [Varid,] Attnum
The netCDF ID, returned from a previous call to NCDF_OPEN or NCDF_CREATE.
The netCDF variable ID, returned from a previous call to NCDF_VARDEF or NCDF_VARID, or the name of the variable. If the GLOBAL keyword is set, this argument must be omitted.
An expression containing the number of the desired attribute. The attributes for each variable are numbered from 0 to the number-of-attributes minus 1. Note that the number of attributes can be found using NCDF_VARINQ or NCDF_INQUIRE (to find the number of global variables).
Set this keyword to return the name of one of the global attributes.