Specification of input/output arguments; .f file

Instead of editing the interface file, we can add special F2PY comments in the Fortran source code:

       subroutine somef(i1, i2, o1, o2, o3, o4, io1)
       real*8 i1, i2, o1, o2, o3, o4, io1
Cf2py  intent(in) i1
Cf2py  intent(in) i2
Cf2py  intent(out) o1
Cf2py  intent(out) o2
Cf2py  intent(out) o3
Cf2py  intent(out) o4
Cf2py  intent(in,out) io1

Now a single F2PY command generates correct interface:

f2py -m hw -c hw.f