macos - Fortran codes won't compile on Mac with gfortran

Question

I recently moved from the SGI, Sun workstation environment to a Mac. SGI and Sun came with Fortran compilers so I have maybe 100 small f77 codes I wrote over the years for post-processing and analysis of simulated data. I was hoping to get these codes running on my iMac with gfortran. Most of these are very simple codes but I can't get them to compile and execute. I tried starting with the basics and wrote the Hello World code from a gfortran help page. My code, fortran.f is:

program helloworld
print *, "hello world"
end program helloworld

When I tried compiling this according to the example I typed:

gfortran fortran.f

But I keep getting the error message:

FATAL:/opt/local/bin/../libexec/as/x86_64/as: I don't understand 'm' flag!

This is the same error message I get on my other codes. Can someone tell me what I'm doing wrong? I can't think of a simpler example but I can't seem to get it to work.

Answer 1

When it comes to macOS, I think that building form sources is the best approach you can have. You can achieve that quite easily by downloading and compiling GFortran as part of GCC directly from: https://gcc.gnu.org/wiki/GFortran

However, there are few things you have to take care of:

• make sure you have XCode installed, you can get it here

  XCode

  XCode is free of charge

• Make sure you have command line tools

  You can get them either from developer.apple.com

  Command Line Tools

  or directly from XCode. It might be that XCode will tell you to install Command Line Tools upon first execution

  

  In the past, running command like "svn", when Command Line Tools were not installed, also triggered the installation.

• Compile GCC

  > ./configure --prefix=$HOME/opt/usr/local
  > make all
  > make install
  

• Alternatively, you can install using macOS package from GFortran

  gfortran-6.3-Sierra.dmg

Fully working sample with Fortran based MPI code:

http://www.owsiak.org/running-open-mpi-on-macos/