VB 动态连接库问题

C/C++ code:
//dll2.cpp
void _stdcall add (void (*cc)())
{
cc();
}
//dll2.def
EXPORTS
add



VB code:
'VB中模块中内容
Declare Function add Lib "dll2.dll" (???????????????'这里应该什样写)

'VB
Private Sub Form_Load()
Call add(a)'这里这样写???????????
End Sub

Sub a()
MsgBox "A"
End Sub

---

Private Sub Form_Load()
    Call add(AddressOf a)
End Sub