Hey folks.

We only mention UCS-2 in [depr.locale.stdcvt.req]

Referring to UCS-2 forces to carry a reference to ISO 10646:2003, as this encoding has long been obsoleted.

We could remove it entirely by rewording slightly, without changing any effect.

For the facet codecvt_utf8:

The facet shall convert between UTF-8 multibyte sequences and UCS-2 or UTF-32 (depending on the size of Elem) within the program.

The facet shall convert between UTF-8 multibyte sequences and UTF-16 or UTF-32 (depending on the size of Elem) within the program.
When converting to UTF-16 if any UTF-8 sequence encodes a codepoint outside of the BMP, the behavior is undefined.

For the facet codecvt_utf16:

The facet shall convert between UTF-16 multibyte sequences and UCS-2 or UTF-32 (depending on the size of Elem) within the program

The facet shall convert between UTF-16 multibyte sequences and UTF-16 or UTF-32 (depending on the size of Elem) within the program.
When converting to UTF-16 if any UTF-8 sequence encodes a codepoint outside of the BMP, the behavior is undefined.

What do you think?

Corentin