C++ DLL calling callback function in VB

[DNA7433]

is it possible for VB to send a function pointer to a C++ DLL and have the DLL call that function?

the VB function is in a standard module and i used this typedef in C++

typedef void (__stdcall *FUNC_PTR)(long);

and i suppose it passes the value right but when i call the function like this

(*callback)(i);

where i have this in the DLL function arguement list

FUNC_PTR callback

is gives one of those illegal operation errors from windows

[CornedBee]

Make sure the VB function is declared as
Public Sub SomeFunc(ByVal param As Long)
'...
End Sub

and you pass it using AdressOf

[DNA7433]

it still gives an error

[Kevin_0011]

It is very difficult to do the programming in VB (i.e. setting the AddressOf parameters properly, etc.). Make sure that it is correct.

[DNA7433]

setting addressof parameters? isn't there only one parameter? and thats to a function i wrote in a module

[CornedBee]

The callback worked for me by using your typedef and writing:

Declare Function MyFunc Lib "mylib.dll" (ByVal addrCallback As Long)
 
Public Sub CB(ByVal l As Long)
  Debug.print Format(l) 
End Sub
 
' In a function
MyFunc(AddressOf(CB))

typedef void (__stdcall *CBFUNC)(long);

void __stdcall MyFunc(CBFUNC f)
{
  f(5);
}