On Success ActiveX methods will have a return value relevant to their function. On failure, the return value will be zero.
If the library was not initialized properly, an exception will be thrown. To get extended error information, call GetLastErrorMsg.
On Failure, most DLL functions will return zero (NULL). To get extended error information, call GetLastErrorMsg.
On success, DLL methods that return a HANDLE will return a handle for the virtual printer that will be used as an argument for other method calls. The hPrinter handle returned by the functions is not to be confused with the hPrinter handle returned by the Windows API OpenPrinter and CreatePrinter functions.