Calling a dll created in VB6 from F#

Question

I am trying to call a dll file created in vb6 from F#. I have written the following dll.

Public Function AddTwoNumbers(ByVal a As Integer, ByVal b As Integer)
    AddTwoNumbers = a + b
End Function

Now I want to call it in my F# program, I wrote this code

open System.Runtime.InteropServices

module InteropWithNative =
   [<DllImport(@"C:\add", CallingConvention = CallingConvention.Cdecl)>]  
   void AddTwoNumbers(int, int)

InteropWithNative.AddTwoNumbers(3,4)

let result = AddTwoNumbers_ 2.0 3.0

It gives me errors and doesn't recognize the function.

Answer 1

带有EntryPoint的工作互操作示例

open System.Runtime.InteropServices // for DllImport

module KernelInterop = 
    [<DllImport("kernel32.dll", EntryPoint="Beep")>]
    extern void Beep( int frequency, int duration )

KernelInterop.Beep  // val Beep : int * int -> unit
KernelInterop.Beep(440, 1000)