std::use_facet
From cppreference.com
| Defined in header <locale>
|
||
| template< class Facet > const Facet& use_facet( const std::locale& loc ); |
||
Obtains a reference to a facet implemented by loc. Facet should be a facet class whose definition contains the public static member id.
Contents |
Parameters
| loc | - | the locale object to query |
Return value
Returns a reference to the facet. The reference returned by this function is valid as long as any std::locale object refers to that facet.
Exceptions
std::bad_cast if std::has_facet<Facet>(loc) == false.
Example
Display the 3-letter currency name used by the user's preferred locale
Run this code
#include <iostream> #include <locale> int main() { std::locale loc = std::locale(""); // user's preferred locale std::cout << "Your currency string is " << std::use_facet<std::moneypunct<char, true>>(loc).curr_symbol() << '\n'; }
Possible output:
Your currency string is USD
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 31 | C++98 | the returned reference remained usable as long as the locale value itself exists |
the returned reference remains usable as long as some locale object refers to that facet |
| LWG 38 | C++98 | there was no requirement on Facet | requirement added |
See also
| set of polymorphic facets that encapsulate cultural differences (class) | |
| checks if a locale implements a specific facet (function template) |
