Mixed Model Programming - Thunk Procedure

MRESULT EXPENTRY ThunkProc16to32(HWND hwnd,       /* Window handle       */
                                 ULONG ulMsg,     /* Message identifier  */
                                 MPARAM mp1,      /* Message parameters  */
                                 MPARAM mp2,
                                 PFNWP wpWindow); /* Window procedure    */
{
        switch (ulMsg)
               {
               case WMP_MSG1:
                    mp1=DosSeltoFlat(mp1);        /* Thunk parameters    */
                    mp2=DosSeltoFlat(mp2);
                    break;
               case WMP_MSG2:
                    mp1=DosSeltoFlat(mp1);        /* Thunk 1st parameter */
                    break;
               }
        return((*wpWindow)(hwnd,                  /* Call window proc    */
                           ulMsg,
                           mp1,
                           mp2));
}