Annex C (informative) Compatibility [diff]

C.5 C standard library [diff.library]

C.5.4 Modifications to behavior [diff.mods.to.behavior]

C.5.4.1 Macro offsetof(type, member-designator) [diff.offsetof]

The macro offsetof, defined in <cstddef> ([cstddef.syn]), accepts a restricted set of type arguments in this International Standard.
Subclause [support.types.layout] describes the change.