Re: [Matlisp-users] Question wrt interface to Allegro

[Raymond T. <ray...@er...>]

>>>>> "Nicolas" == Nicolas Neuss <ne...@ma...> writes:

    Nicolas> Comparing with Matlisp, I have found my bug.
    Nicolas> Nicolas Neuss <ne...@ma...> writes:

    >> (foreign-functions:def-foreign-call (dnrm2- "dnrm2_")
    Nicolas>                                               "dnrm2" is correct

    >> ((n :int) (x (:array :double)) (incx :int))
    >> :convention :fortran
    >> :returning :double)

    Nicolas> To make sure I understand this correctly: dnrm2_ is probably a routine
    Nicolas> suitable for calling from C (passing arrays as a pointer to values) while
    Nicolas> Allegro with convention :fortran passes arrays pointing to values-1 as is
    Nicolas> suitable for the Fortran "dnrm2".

I don't know what the :fortran convention means, but your explanation
sounds plausible.  It seems a little odd to me.  For n and incx, I can
see the :fortran convention to mean pass the address of the location
of n and incx to the routine, since that's what Fortran does
(everything is pass by reference).  Arrays are a bit trickier.  I
don't see why you want to pass the address of x-1 instead of just x.
After all, Fortran x(1) is the first element of the array, however
that array might be arranged in memory.

Ray