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[netCDF #CDY-638973]: Bug in NetCDF library

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  • Subject: [netCDF #CDY-638973]: Bug in NetCDF library
  • Date: Mon, 02 Apr 2007 15:13:27 -0600
> Dear Unidata,
> 
> I have been using the NetCDF library for some time now to create and read 
> classic format files. However, recently I found the need to use the new 
> 64-bit offset format to store large datasets. The problem is that, in the C++ 
> interface to the library, there is a bug that prevents the creation of 
> anything else but classic files. Though I'm using version 3.6.0-p1, I've 
> found that the problem continues to exist in the latest release (3.6.2).
> 
> The responsible code is located in the NcFile::NcFile(...) constructor:
> 
> NcFile::NcFile( const char* path, FileMode fmode, size_t* chunksizeptr, 
> size_t initialsize, FileFormat fformat  )
> {
> NcError err(NcError::silent_nonfatal); // constructor must not fail
> 
> int mode = NC_NOWRITE;
> the_fill_mode = Fill;
> int status;
> 
> // If the user wants a 64-bit offset format, set that flag.
> if (fformat == Offset64Bits)
> mode |= NC_64BIT_OFFSET;
> 
> switch (fmode) {
> case Write:
> mode = NC_WRITE;
> /*FALLTHRU*/
> case ReadOnly:
> [...]
> 
> As you can see, when the file format is requested to use 64-bit offsets, the 
> mode variable is set appropriately but then, when the switch-case is entered 
> next, the mode variable is overwritten with whatever file mode selected. This 
> prevents the 64-bit format flag to ever reach the actual creation of the 
> NetCDF file, so it is always created with the classic format.
> 
> Do you think this could be fixed by then next release? An easy solution would 
> be to move the 64-bit flag setting before the FALLTHRU comments in the 
> switch-case... In any case, thanks for the great work you have performed by 
> creating and supporting this library.
> 
> Kind regards.
> 
> ________________________________
> 

Thanks for pointing this out! I have fixed this, and the fix is in the latest 
netCDF-3 snapshot:
http://www.unidata.ucar.edu/software/netcdf/builds/snapshot/

I have also modified the C++ test so that it checks the format of the test file.

Thanks again!

Ed
> 
> Oscar Portela Arjona
> 
> Ingeniero Inform�tico /
> 
> Software Engineer
> 
> 
> 
> 
> GMV AEROSPACE
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> 
> 
> 
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Ticket Details
===================
Ticket ID: CDY-638973
Department: Support netCDF
Priority: Urgent
Status: Closed