Calling a VB DLL from Fortran code.

[ashok_c]

I want to call a VB subroutine from Fortran code.
this subroutine must be in VB Dll.
Please illustrate with a sample code.
Thanks,
Ashok

[martin_wardle]

This is what I am trying to also. What follows will not help very much because it does not work. But if someone knows what I am doing wrong, it should answer your question also.

In the CFV help there are some samples using the Fortran Module Wizard and COM. Following the steps there you can generate a wrapper module in Fortran toassist incalls to the (VB generated) DLL. The compiled code runs , but crashes with an access violation when trying to access the DLL. My test function was simply a VB Sub compiled as a dll project.

Public Sub Add2(InVar As Single, OutVar As Single)
OutVar = InVar + 2#
End Sub

Itried setting the instancing to different options - no effect.

In the fortram main program I had:

PROGRAM MAIN

USE TESTMOD

IMPLICIT NONE

INTEGER OBJREF, STAT

REAL*4 JUNKVARIN,JUNKVAROUT

CALL COMINITIALIZE(STAT)

CALL COMCreateObjectByGUID (CLSID_Add2, CLSCTX_ALL, IID__Add2, OBJREF, STAT)

JUNKVARIN=2.0

CALL $Add2_Add2(OBJREF,JUNKVARIN,JUNKVAROUT)

WRITE(6,*) JUNKVARIN,JUNKVAROUT

STOP
END

TESTMOD was the wrapper module generated by the wizard and was included in the build.

Thanks - have not done this much before - apologies in advance if I have violated the message board rules and etiquette in any way.

[durisinm]

I doubt that this will help solve your problem, but if I were you I wouldn't use the double-precision 2# constant in a calculation with single-precision variables. I would either make OutVar and InVar double precision or change the double-precision 2# constant to single-precision 2!.

Mike D