Annex C (informative) Compatibility [diff]

C.5 C standard library [diff.library]

C.5.2 Modifications to definitions [diff.mods.to.definitions]

C.5.2.1 Types char16_­t and char32_­t [diff.char16]

The types char16_­t and char32_­t are distinct types rather than typedefs to existing integral types.
The tokens char16_­t and char32_­t are keywords in this International Standard.
They do not appear as macro names defined in <cuchar>.