NAME
        CallErrHook -- internal call of error hook

   SYNOPSIS
        result = (*PrinterData->pd_CallErrHook)(hook, iorequest, msg);
        D0

        long callerrhook(struct hook *, struct iorequest *, struct prterrmsg *);

   FUNCTION
        An application can set an error hook that is called in case of
        errors to display an formated and localized error message to the
        user. The driver can set an error hook to format and localize
        custom error messages and to call the application's error hook. This
        is done by calling PD->pd_CallErrHook() from the printer.device.
        CallErrHook will do additional formating like setting a title of
        the error message if no is set by the driver and then calls the
        application's error hook.

   RESULT
        The return value of the hook is returned from CallErrHook.