c++ dll returning string

i have no idea how to return a string from my dll here is some code i have so far

main.cpp

Code:

---

char *__stdcall myfunction(char * variable)
{
        return variable;
}

---

main.def

Code:

---

EXPORTS
      myfunction

---

vb code

Code:

---

Private Declare Function myfunction  Lib "my.dll" (ByVal variable As String) As String
 -----
MsgBox myfunction("test")

---

whats wrong i get a message saying it cant read the memory and also one that says it cant write to the memory... thanks for the help.

nm that works, but when i try to do a strcpy it crashes the dll and says it wont work? does anyone have an idea for that?