long année = 1990L; uses Unicode letters directly in a C identifier, whereas escaped forms such as \u00E9 provide a portable intermediate representation. section 9.3
UAX #31 defines Unicode rules for identifiers and syntax. C23 refers to it when specifying allowed identifier characters and addresses equivalent character sequences through Normalization Form C. section 9.3
Canonical composition
The sequence é can decompose as e plus an acute accent and recompose as é: \u00E9 → \u0065\u0301 → \u00E9. Form C also maps equivalent representations such as the Angstrom sign to Å.
Compatibility of Greek-derived signs
Normalization likewise maps the Ohm sign to the Greek capital omega: Ω → Ω → Ω and Ω → Ω → Ω.
