Define versus Data Mode

16.4 Define versus Data Mode

NetCDF-4 doesn't require distinguishing between calls that are restricted to "define mode" or "data mode".

For classic and 64-bit offset files, define and data mode are explicitly managed by the user, with nc_redef and nc_enddef calls.
For netCDF-4 files, data and define mode can be left to netCDF-4. The mode will be switched as needed.
So calls to nc_enddef and nc_redef can be removed.
This automatic mode switching is turned off for files created with CLASSIC_MODEL flag.