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std::locale::id(3cxx) std::locale::id(3cxx)

NAME

std::locale::id - Facet ID class.

The ID class provides facets with an index used to identify them. Every facet class must define a public static member locale::id, or be derived from a facet that provides this member, otherwise the facet cannot be used in a locale. The locale::id ensures that each class type gets a unique identifier.

SYNOPSIS

Public Member Functions


id ()
Constructor. size_t _M_id () const throw ()

Friends


template<typename _Facet > bool has_facet (const locale &) throw ()
Test for the presence of a facet.

has_facet tests the locale argument for the presence of the facet type provided as the template parameter. Facets derived from the facet parameter will also return true. " class locale
class locale::_Impl
template<typename _Facet > const _Facet & use_facet (const locale &)
Return a facet.

use_facet looks for and returns a reference to a facet of type Facet where Facet is the template parameter. If has_facet(locale) is true, there is a suitable facet to return. It throws std::bad_cast if the locale doesn't contain a facet of type Facet. "

Detailed Description

Facet ID class.

The ID class provides facets with an index used to identify them. Every facet class must define a public static member locale::id, or be derived from a facet that provides this member, otherwise the facet cannot be used in a locale. The locale::id ensures that each class type gets a unique identifier.

Definition at line 483 of file locale_classes.h.

Constructor & Destructor Documentation

std::locale::id::id () [inline]

Constructor.

Definition at line 514 of file locale_classes.h.

References std::locale::has_facet, and std::locale::use_facet.

Friends And Related Function Documentation

template<typename _Facet > bool has_facet (const locale &) [friend]

Test for the presence of a facet.

has_facet tests the locale argument for the presence of the facet type provided as the template parameter. Facets derived from the facet parameter will also return true.

Template Parameters:

_Facet The facet type to test the presence of.

Parameters:

__loc The locale to test.

Returns:

true if __loc contains a facet of type _Facet, else false.

Definition at line 104 of file locale_classes.tcc.

template<typename _Facet > const _Facet& use_facet (const locale &) [friend]

Return a facet.

use_facet looks for and returns a reference to a facet of type Facet where Facet is the template parameter. If has_facet(locale) is true, there is a suitable facet to return. It throws std::bad_cast if the locale doesn't contain a facet of type Facet.

Template Parameters:

_Facet The facet type to access.

Parameters:

__loc The locale to use.

Returns:

Reference to facet of type Facet.

Exceptions:

std::bad_cast if __loc doesn't contain a facet of type _Facet.

Definition at line 132 of file locale_classes.tcc.

Author

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Mon Sep 9 2019 libstdc++