Function DdeClientTransaction 

pub unsafe extern "stdcall" fn DdeClientTransaction(
    pData: LPBYTE,
    cbData: DWORD,
    hConv: HCONV,
    hszItem: HSZ,
    wFmt: UINT,
    wType: UINT,
    dwTimeout: DWORD,
    pdwResult: LPDWORD,
) -> HDDEDATA