NAME
        PRD_SETERRHOOK -- set a hook for error messages (V44)

   FUNCTION
        This command sets a hook that will be called if the printer.device
        returns with an error from any other I/O command. This allows
        printer drivers to use private error messages.

   IO REQUEST
        io_Message      mn_ReplyPort set if quick I/O is not possible
        io_Device       preset by the call to opendevice
        io_Command      PRD_SETERRORHOOK
        io_Hook         a pointer to a hook that will be called

        Two standard hook values a defined:

        PDHOOK_NONE     no error hook is to be used
        PDHOOK_STD      EasyRequest() is used to display the error message

        The hook gets a pointer to the iorequest that caused the error as
        the object and a pointer to the following structure as message:

struct prterrmsg {
        ULONG pe_Version;
        ULONG pe_ErrorLevel;
        struct window *pe_window; /* window for easyrequest() */
        struct easystruct *pe_es;
        ULONG *pe_IDCMP;
        aptr pe_arglist;
};
        pe_Version      the message version number PDHOOK_VERSION
        pe_ErrorLevel   one of RETURN_WARN, RETURN_ERROR, RETURN_FAIL
        pe_Window       a window pointer (for EasyRequest()) or NULL
        pe_ES           a pointer to the error message structure
        pe_IDCMP        a pointer to IDCMP Flags for EasyRequest()
        pe_ArgList      a pointer to an array of arguments

        The simplest case is to use that structure to call EasyRequest()
        or to printf() a message to a console (use the error message from
        pe_ES and the pe_ArgList).