Character Encodings (UTF-8)

Permitted Characters in NetCDF Names

The names of dimensions, variables and attributes (and, in netCDF-4 files, groups, user-defined types, compound member names, and enumeration symbols) consist of arbitrary sequences of alphanumeric characters, underscore ‘_’, period ‘.’, plus ‘+’, hyphen ‘-‘, or at sign ‘@’, but beginning with an alphanumeric character or underscore. However names commencing with underscore are reserved for system use.

Beginning with versions 3.6.3 and 4.0, names may also include UTF-8 encoded Unicode characters as well as other special characters, except for the character ‘/’, which may not appear in a name.

Names that have trailing space characters are also not permitted.

Case is significant in netCDF names.

Length of NetCDF Object Names

A zero-length name is not allowed.

Names longer than ::NC_MAX_NAME will not be accepted any netCDF define function. An error of ::NC_EMAXNAME will be returned.

All netCDF inquiry functions will return names of maximum size ::NC_MAX_NAME for netCDF files. Since this does not include the terminating NULL, space should be reserved for NC_MAX_NAME + 1 characters.

Conventions and NetCDF Object Names

Some widely used conventions restrict names to only alphanumeric characters or underscores.

Note that, when using the DAP2 protocol to access netCDF data, there are \em reserved keywords, the use of which may result in undefined behavior. See \ref dap2_reserved_keywords for more information.