README.netcdf4

		     Compiling wgrib2 with netcdf-4

9/2022: wgrib2 v3.1.2beta3
        compiles in Ubuntu 20.04LTS gcc 9.4.0
        compiles in RedHat release 7.9 gcc 4.8.5
        does not compile (hdf5) with AMD clang version 13.0.0

4/2022: netcdf4 seems to be working gcc v9.4.0. clang is a no go.
I am trying to compile on cygwin but it has been compiling for 3 hours.

8/2020:

NetCDF4 support has been in shambles for many years.  The good news,
Redhat with its vintage compilers has been working fine. If you
are using the Intel compilers, it compiles and probably works.


Support:  There is no way to support using XYZ compiler in ABC operating
system.  The user has to test whether their copy of wgrib2 with the NetCDF4 
options works.  Don't assume that "it compiled" means "it worked". I have
seen "it compiled" but "it doesn't work".  The NetCDF4 code seems to be
robust but the hdf5 library is sensitive to the version of the compiler.

Configuration:

In the makefile, change the configuration to 

USE_NETCDF3=0
USE_NETCDF4=1


Then you have to set the environment variables to the C and F90 compilers
and run gnu make.

(bash example)

export CC=gcc               (set the C compiler)
export FC=gfortran          (set the f90 compiler)
make                        (on some machines this gnu make could be called gmake)

The make will respond with an error message that you need to get the netcdf4 source code.
You can get the source code using wget.

make                        (on some machines this gnu make could be called gmake)

The make will respond with another error message that you need to get the hdf5 source code.
You can get the source code using wget.

make                        (third time is a charm)


This has been tested with gcc/gfortran and clang/gfortran on Ubuntu 12.04 (64 bits) and
with gcc/fortran on Redhat 5 and 6 (64-bits).

Notes: UCAR has a web page with help in compiling netcdf.