has_facet

Locale Function

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A function template used to determine if a locale has a given facet.

None

#include <locale>
template <class Facet> bool has_facet(const locale&) throw();

has_facet returns true if the requested facet is available in the locale, otherwise it returns false. You specify the facet type by explicitly providing the template parameter. (See the example below.)

Note that if your compiler cannot overload function templates on return type then you'll need to use an alternative has_facet template. The alternative template takes an additional argument that's a pointer to the type of facet you want to check on. The declaration looks like this:

template <class Facet> 
const bool has_facet(const locale&, Facet*) throw();

The example below shows the use of both variations of has_facet.

//
// hasfacet.cpp
//

#include <iostream>

int main ()
{
  using namespace std;

  locale loc;

#ifndef _RWSTD_NO_TEMPLATE_ON_RETURN_TYPE
  cout << has_facet<ctype<char> >(loc) << endl;
#else
  cout << has_facet(loc,(ctype<char>*)0) << endl;
#endif
 
  return 0;
}

locale, facets, use_facet

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