Annex C (informative) Compatibility [diff]

C.6 C standard library [diff.library]

C.6.5 Modifications to behavior [diff.mods.to.behavior]

C.6.5.2 Macro offsetof(type, member-designator) [diff.offsetof]

The macro offsetof, defined in <cstddef>, accepts a restricted set of type arguments in C++.
Subclause [support.types.layout] describes the change.