"Craig Powers" hal-pc.org> wrote in message
news:47bef912$0$29923$a726171b@news.hal-pc.org...

I didn't necessarily read what you wrote to utab on this. I'll take a
second gander at that thread.

I set a goal for an easier inter-syntax problem and was able to get results:

Main is in fortran:
PROGRAM Vector_Sqrt

IMPLICIT NONE
!add function from c++
real(kind=8), external :: sqrt_from_c

INTEGER, PARAMETER :: dp = KIND(0.0d0)

REAL(DP) :: four_vector(4), j
INTEGER :: i

DO i = 1, 4

j= 1.0*i
four_vector(i) = SQRT_FROM_C(j)
! four_vector(i) = SQRT(REAL(i, DP))
ENDDO

WRITE(*,'(4F19.16)') four_vector

END
! g++ -c cat.cpp && gfortran2 -c vector4.f95
! gfortran2 cat.o vector4.o
,and the sqrt is from c++:

//$ cat v.c
#include

extern "C" double sqrt_from_c_ (double *x)
{
return sqrt(*x);
}

// g++ -c cat.cpp

Much of this notation is mixed and sloppy. I'd been playing around with
different things and got this to work. I still don't know what cat would
mean to FX. I did find out that the double ampersand *does* work on dos
and comes highly recommended when using multiple commands.

I'll clean up this notation and try to get squared away with a dotproduct,
which doesn't require much more than a sqrt. It's not surprising that
passing a pointer to a real would be effective here. It would seem that
adding extern "C" and a trailing underscore is what works.

Thanks for your help.