Set environment variables for compilers

The sample GNU and Intel environment files set the environment variables listed below in order to select the desired C, C++, and Fortran compilers:

Environment variables that specify compilers
Variable	Specifies the:	GNU name	Intel name
`CC`	C compiler	`gcc`	`icx`
`CXX`	C++ compiler	`g++`	`icx`
`FC`	Fortran compiler	`gfortran`	`ifort`

Note

GEOS-Chem Classic only requires the Fortran compiler. But you will also need the C and C++ compilers if you plan to build other software packages (such as KPP) or install libraries manually.

Also, older Intel compiler versions used icc as the name for the C compiler and icpc as the name of the C++ compiler. These names have been deprecated in Intel 2023 and will be removed from future Intel compiler releases.

The commands used to define CC, CXX, and FC are:

# for GNU
export CC=gcc
export CXX=g++
export FC=gfortran

or

# for Intel
export CC=icx
export CXX=icx
export FC=ifort