README.macos

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#                 copyright 2020, BP America Inc.                     #
#                        All Rights Reserved                          #
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File: $DDSROOT/README.macos

NOTE: The default development environment from Apple Xcode does not
      support either OpenMP or Fortran. Therefore, it is much easier
      to build DDS with third-party compilers and libraries.

 1) Install Homebrew - https://brew.sh

 2) Install gcc and and openmpi from Homebrew.

 3) Define the following environment variables:

    OMPI_CXX=g++-9
    OMPI_CC=gcc-9
    OMPI_FC=gfortran-9
    COMPILER=gfortran-9

    Use the approriate version suffix according to the gcc version that you
    installed from Homebrew. The suffix must be present to avoid confusion
    with Apple's gcc wrapper, which actually points to their version of clang
    compiler.
 
    DDSROOT and DDS_DIST must be defined as per general DDS installation
    documentation.

 4) Using the general build instructions, compile and install libhost, libgio, and libdds3.

 5) Build and install pre-packaged fftw.

 6) Build and install libfft using the general build instuctions.

NOTE: Some Fortran DDS applications may refuse to compile with the latest
      version of gfortran (9.2 at the time of this writing). This is a bug
      in gcc, which can be addressed by adding the following line in each
      application's Makefile:

      include ${DDSROOT}/etc/MakeVariables
      FCFlags := ${FCFlags} -std=legacy
      include ${DDSROOT}/etc/MakeRules