Nonencapsulated Unions
A nonencapsulated union is a union which is not contained in a structure with its discriminant. The nonencapsulated union is indicated by the presence of the type attribute [switch_type] and the field attribute [switch_is].
For a description of the form of an nonencapsulated union, see union.
The shape of unions must be the same across platforms to ensure interconnectivity.
For more information, see Encapsulated Unions, union, [switch_is] and [switch_type].