137. Do use_facet and has_facet look in the global locale?

Section: 25.3.1 [locale] Status: TC1 Submitter: Angelika Langer Opened: 1999-03-17 Last modified: 2016-02-10

Priority: Not Prioritized

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Discussion:

Section 25.3.1 [locale] says:

-4- In the call to use_facet<Facet>(loc), the type argument chooses a facet, making available all members of the named type. If Facet is not present in a locale (or, failing that, in the global locale), it throws the standard exception bad_cast. A C++ program can check if a locale implements a particular facet with the template function has_facet<Facet>().

This contradicts the specification given in section 25.3.2 [locale.global.templates]:

template <class  Facet> const  Facet& use_facet(const locale&  loc);

-1- Get a reference to a facet of a locale.
-2- Returns: a reference to the corresponding facet of loc, if present.
-3- Throws: bad_cast if has_facet<Facet>(loc) is false.
-4- Notes: The reference returned remains valid at least as long as any copy of loc exists

Proposed resolution:

Remove the phrase "(or, failing that, in the global locale)" from section 22.1.1.

Rationale:

Needed for consistency with the way locales are handled elsewhere in the standard.