[DllImport("msi.dll", CharSet = CharSet.Auto)]
public static extern int MsiExtractPatchXMLData(
[MarshalAs(UnmanagedType.LPTStr)] string szPatchPath,
IntPtr pvReserved,
[MarshalAs(UnmanagedType.LPTStr)] StringBuilder lpXmlDataBuf,
ref int pcchXmlDataBuf
);