My workflow involves importing Fortran subroutines into R to work with very large vectors and matrices. My gfortran compiling options are as follows:
gfortran -fimplicit-none -ffree-line-length-0 -fdefault-integer-8 -fdefault-real-8 -fpic -shared fortran_file.f95 -o fortran_file.so
I find these options very convenient to use. I would like to ask whether these options can bring unexpected errors. I am not concerned about portability since I only distribute the so files and other R users just call them from R.