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4088.println ignores the locale imbued instd::ostream

Section: 31.7.6.3.5[ostream.formatted.print]Status:WPSubmitter: Jens MaurerOpened: 2024-04-30Last modified: 2024-11-28

Priority:Not Prioritized

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Discussion:

31.7.6.3.5[ostream.formatted.print] specifies thatstd::print uses the localeimbued in thestd::ostream& argument for formatting, by using this equivalence:

vformat(os.getloc(), fmt, args);

(in thevformat_(non)unicode delegation).

However,std::println ignores thestd::ostream's localefor its locale-dependent formatting:

print(os, "{}\n", format(fmt, std::forward<Args>(args)...));

This is inconsistent.

[2024-10-03; Reflector poll]

Set status to Tentatively Ready after seven votes in favour during reflector poll.

[Wrocław 2024-11-23; Status changed: Voting → WP.]

Proposed resolution:

This wording is relative toN4981.

1. Modify 31.7.6.3.5[ostream.formatted.print] as indicated:

   template<class... Args>  void println(ostream& os, format_string<Args...> fmt, Args&&... args);

   -2-Effects: Equivalent to:

   print(os, "{}\n", format(os.getloc(), fmt, std::forward<Args>(args)...));