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Re: 951210: netCDF irrational behavior?

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  • Subject: Re: 951210: netCDF irrational behavior?
  • Date: Mon, 11 Dec 1995 11:00:50 -0700
Nan,

> thanks for your email.  I tried using the workaround
> you suggested (in this case it was required because the
> new name was longer than the old) but it doesn't work
> for me.  did you get it to work somehow?  Maybe there
> is a little trick I am missing (?)

Here's what I did to verify the workaround:

First, I created a netCDF test file, by creating the file dbug.cdl:
--------------------- dbug.cdl ------------------------------------
netcdf dbug {
dimensions:
        row = 2;
        col = 3;
variables:
        float a(row,col);
}
-------------------------------------------------------------------
and running

    $ ncgen -n dbug.cdl

to create the file "dbug.nc".

Then I created the following C program to demonstrate the error:

---------------------- nan.c --------------------------------------
#include <netcdf.h>

main()
{
    int ncid = ncopen("dbug.nc",NC_WRITE);
    int did;

    ncredef(ncid);              /* enter define mode */
    did = ncdimid(ncid, "row");
    ncdimrename(ncid,did,"rows");
    ncendef(ncid);

    did = ncdimid(ncid, "rows");
    ncdimrename(ncid,did,"row");

    ncredef(ncid);              /* enter define mode */
    did = ncdimid(ncid, "row");  /* FAILS: ncdimid: dim "row" not found */
    ncdimrename(ncid,did,"rows");
    ncendef(ncid);

    ncclose(ncid);
}
-------------------------------------------------------------------

When I compiled and linked with the latest beta release of netCDF 2.4, it
duplicated the problem you saw:

    $ cc -g -I../libsrc nan.c -o nan -L../libsrc -lnetcdf -lnsl
    $ ncgen -b dbug.cdl
    $ ./nan
    ncdimid: dim "row" not found

When I inserted calls to ncredef(ncid) and ncendef(id) around the middle
ncdimid and ncdimrename calls, as in:

    ncredef(ncid);              /* enter define mode */
    did = ncdimid(ncid, "rows");
    ncdimrename(ncid,did,"row");
    ncendef(ncid);

and recreated the "dbug.nc" file before running this new test, everything
worked fine.

--Russ