[Numpy-discussion] Attempting to wrap a Fortran-77 subroutine using f2py but I haven't been able to understand what is causing the error

I'm attempting to wrap a Fortran-77 source member using f2py. I'm running he Anaconda distribution for Python 3.7.6 on a Mac Pro (2019) under Mac OS X Catalina (ver. 10.15.6). The version of NumPy I'm running is 1.18.3. I've attached a copy of the Fortran source code to this note (see rkfn78.for). The command I'm using to wrap this code is f2py3 -c rkfn78.for --fcompiler=gfortran --f77flags="-c -O -Wall" -m rkfn78 The output I get is captured in the file rkfn78_build_output.txt. I don't understand the cause behind the error message I get, so any advice would be welcomed. Sam Dupree.