On the check_type method we check that the underlying type is either short or unsigned int. https://gitlab.com/tango-controls/cppTango/-/blob/main/src/include/tango/server/w_attrsetval_templ.h?ref_type=heads#L81 We then cast to short so the unsigned int version should not work, or can lead to bug. We should not allow for it, or check bounds, if it's needed for backward compatibility.