Defined in header <locale> | ||
|---|---|---|
template< class Facet > bool has_facet( const locale& loc ) throw(); | (until C++11) | |
template< class Facet > bool has_facet( const locale& loc ) noexcept; | (since C++11) |
Checks if the locale loc implements the facet Facet.
| loc | - | the locale object to query |
Returns true if the facet Facet was installed in the locale loc, false otherwise.
#include <iostream>
#include <locale>
// minimal custom facet
struct myfacet : public std::locale::facet {
static std::locale::id id;
};
std::locale::id myfacet::id;
int main()
{
// loc is a "C" locale with myfacet added
std::locale loc(std::locale::classic(), new myfacet);
std::cout << std::boolalpha
<< "Can loc classify chars? "
<< std::has_facet<std::ctype<char>>(loc) << '\n'
<< "Can loc classify char32_t? "
<< std::has_facet<std::ctype<char32_t>>(loc) << '\n'
<< "Does loc implement myfacet? "
<< std::has_facet<myfacet>(loc) << '\n';
}Output:
Can loc classify chars? true Can loc classify char32_t? false Does loc implement myfacet? true
| set of polymorphic facets that encapsulate cultural differences (class) |
|
| obtains a facet from a locale (function template) |
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