The <cxxUnionDetail> element provides detailed information about the structure and behaviors of the C++ union.
The <cxxUnionDetail> element is defined within <cxxUnion>. In <cxxUnionDetail> the <example> and <section> elements are provided to support the current specific C++ API reference. A union body can contain declarations of the members of the union, such as variables, classes, structs, and functions.
apiDesc, apiImpl, cxxUnionDefinition example, section,
(cxxUnionDefinition (optional) then apiDesc, then (example, or section, or apiImpl, (any number) ))