Fortran dll

Question

Hello,
I am beating my head against the wall trying to get a fortran DLL to work in labview.
The DLL has multi-dimensional array inputs, and my guess is that my problem lies in correctly configuring the Call LibraryFunction.
The dll is very complex, but I know the dll works, because I have a visual basic program that calls the dll, and it works fine.
A simplified version of the DLL variable definition from the Fortran code is shown below:
      Subroutine MyFunction(Numx,V,dz,ep,nx,top,D)
c
c    ***    Set DLL Attributes   ***
c
!DEC$ ATTRIBUTES DLLEXPORT :: MyFunction
!DEC$ ATTRIBUTES ALIAS:'MyFunction' :: MyFunction
c
c      *** Declare Variables ***
      implicit real*8 (r-w)
      integer sizex,sizey,sizez
      parameter (sizex = 50,sizey = 50,sizez = 20)
c
c    *** Variables passed from the control routine ***
c
    integer D                                           
    integer Numx               
          real*8 V(0:sizex,0:sizey,0:3*sizez)       
    real*8 dz                           
    real*8 ep(2)                           
          real*8 nx(0:sizex,0:sizey,0:sizez)       
         integer top(0:sizex,0:sizey)                                                      
c
c    *** The rest of the program ***
As you can see the inputs consist of Integers, 2D integer arrays, 3D double arrays, a 1d double array, and double inputs.
When I configure the call library function I have tried both calling conventions (C and stdcall) I have defined the integers as I32 (signed integers), I have configured the arrays as Array Format=Array Data Pointer.  The input arrays have been pre-defined in labview as: V is 50x50x60, nx is 50x50x20, top is 50x50 and ep=2, which is the array size that they are defined in the fortran program.
I have tried all the different values for Array Format.  I have tried both calling conventions and both thread selections.  I'm working in LV 8.5
Everytime I try to run the program I get and error 1097 (An exception occured within external code).
I'm almost certain that the problem lies with how I'm configuring the DLL call.
I also have a dll called DFORMD.dll in the working directory (I'm pretty sure it's suppose to be there, but I don't know what to do with it).
The suggestion from my phone call to ni support was to wrap the fortran dll in a C dll, because labview cannot use fortran calling conventions.  However, the posts on this forum seem to suggest that I should be able to use the fortran DLL directly.
Any help would be appreciated.
Neil

Answer 1

According to this page
http://blogs.msdn.com/oldnewthing/archive/2004/01/02/47184.aspx
Fortran calling convention is the same as Pascal calling convention and according to
this wikipedia article
http://en.wikipedia.org/wiki/X86_calling_conventions
Pascal and stcall conventions are both callee clean-up convention, but the parameters
are passed to stack in different order. This might be the problem.
You could try to make a Fortran function with only one parameter and try to call that with stdcall convention.
In case of parameter, it does not matter in which order the parameters are passed to stack.
Maybe you can change the calling convention in your Fortran code when creating the DLL.
Unfortunately I don't know anything about Fortran, but hopefully this helps and gives you some ideas for this.