Are UTF16 (as used by for example wide-winapi functions) characters always 2 byte long?

Question

Please clarify for me, how does UTF16 work? I am a little confused, considering these points:

• There is a static type in C++, WCHAR, which is 2 bytes long. (alway

Answer 1

Windows' WCHAR is 16 bits (2 bytes) long.

A Unicode codepoint may be represented by one or two of these WCHAR – 16 or 32 bits (2 or 4 bytes).

wcslen returns number of WCHAR units in a wide string, while wcslen_l returns the number of (locale-dependent) codepoints. Obviously, wcslen <= wcslen_l.

A Unicode character may consist of multiple combining codepoints.