Le mer. 24 janv. 2024 à 17:50, Steve Downey <sdowney@gmail.com> a écrit :

I'd missed the discouraged part. Is that also the case for Angstrom, I hope?

Le mer. 24 janv. 2024 à 18:52, Eddie Nolan via SG16 <sg16@lists.isocpp.org> a écrit :

With respect to unit symbols whose Unicode code points as units have canonical equivalents as Greek letters, this was previously brought up in the telecon on November 29, 2023 (minutes), where I pointed out that the existing precedent in the standard is to use the unit version, since iostream formatting of std::chrono::duration uses U+00B5 (MICRO SIGN) rather than U+03BC (GREEK SMALL LETTER MU) for microseconds. (See [time.duration.io]p(1,5)).

Those cases are distinct; I suppose I should have quoted more context.

The Unicode Standard reads, in Section 7.2 Greek, sub Greek Letters as Symbols,

For compatibility purposes, a few Greek letters are separately encoded as symbols in other character blocks. Examples include U+00B5 µ MICRO SIGN in the Latin-1 Supplement character block and U+2126 Ω OHM SIGN in the Letterlike Symbols character block. The ohm sign is canonically equivalent to the capital omega, and normalization would remove any distinction. Its use is therefore discouraged in favor of capital omega. The same equivalence does not exist between micro sign and mu, and use of either character as a micro sign is common. For Greek text, only the mu should be used.

ANGSTROM SIGN is, as Steve hopes, like OHM SIGN in that respect (see Section 22.2, sub Unit Symbols).

Best regards,

Robin Leroy