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[netCDF #QMC-939658]: NetCDF library naming conventions

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  • Subject: [netCDF #QMC-939658]: NetCDF library naming conventions
  • Date: Wed, 18 Jul 2007 21:37:02 -0600
Hi Robert,

You can make a simple local modification to the netCDF-3 library source to
allow arbitrary characters in names.  Just change the NC_check_name() function
in libsrc/string.c to not check the characters in names by removing the for
loop in that function.  Everything should still compile and link fine, but if
you run "make check" there will be some failed tests corresponding to checking
that illegal characters in names get an error return.

This will give you an up-to-date version of netCDF-3 that doesn't enforce name
checks, but won't solve the problems with IDL, unless IDL links dynamically to
the netCDF library.  If IDL has a statically linked version of the library, I
think all you can do is request the IDL vendor (ITT?) to make a version that
links dynamically to netCDF, or make a version that links statically to your
custom netCDF library, or get the IDL source so you can do this yourself.  Any
of these alternatives be impractical or expensive.

If you continue to create netCDF files with spaces in variable names, there may
be other netCDF applications and utilities that will have problems with these
files.  For example, the ncgen utility will not work properly with a variable
name that comtains spaces, because the grammar for CDL (the text notation for
netCDF data supported by ncdump and ncgen) requires constraints on names for
variables, dimensions, and attributes.  Because of potential problems like
this, we will not distribute an alternate version of netCDF-3 that does not
enforce naming conventions, but it's easy for you to create such a version, as
described above.  NetCDF-4 permits Unicode names that are UTF-8 encoded, and
it's possible that will require removing some naming constraints, but that is
currently unexplored (and untested) territory.  A beta-test version of netCDF-4
is available, if you want to test it.

Sorry about the problems caused by not enforcing the name constraints in
version 2.4, but that's now a very old and unsupported version ...

--Russ



Russ Rew                                         UCAR Unidata Program
address@hidden                     http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: QMC-939658
Department: Support netCDF
Priority: Normal
Status: Closed