NAME¶

std::wstring_convert::wstring_convert - std::wstring_convert::wstring_convert

Synopsis¶

wstring_convert() : wstring_convert( new Codecvt ) {} (1)
explicit wstring_convert( Codecvt* pcvt ); (2)
wstring_convert( Codecvt* pcvt, state_type state ); (3)
explicit wstring_convert( const byte_string& byte_err,
const wide_string& wide_err = (4)
wide_string() );
wstring_convert( const std::wstring_convert& ) = delete; (5) (since C++14)

1) Default constructor.
2) Constructs the wstring_convert object with a specified conversion facet, using
default-constructed values for the shift state and the error strings.
3) Constructs the wstring_convert object with a specified conversion facet and
specified shift state, using default-constructed values for the error strings.
4) Constructs the wstring_convert object with specified error strings, using new
Codecvt as the conversion facet and the default-constructed state_type as shift
state.
5) The copy constructor is deleted, wstring_convert is not CopyConstructible.

Parameters¶

pcvt - pointer to the conversion facet of type Codecvt (behavior is undefined if
this pointer is null)
state - initial value of the conversion shift state
byte_err - narrow string to display on errors
wide_err - wide string to display on errors

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
P0935R0 C++11 default constructor was explicit made implicit

Example¶

// Run this code

#include <codecvt>
#include <locale>
#include <utility>

// utility wrapper to adapt locale-bound facets for wstring/wbuffer convert
template<class Facet>
struct deletable_facet : Facet
{
using Facet::Facet; // inherit constructors
~deletable_facet() {}
};

int main()
{
// UTF-16le / UCS4 conversion
std::wstring_convert<
std::codecvt_utf16<char32_t, 0x10ffff, std::little_endian>
> u16to32;

// UTF-8 / wide string conversion with custom messages
std::wstring_convert<std::codecvt_utf8<wchar_t>> u8towide("Error!", L"Error!");

// GB18030 / wide string conversion facet
typedef deletable_facet<std::codecvt_byname<wchar_t, char, std::mbstate_t>> F;
std::wstring_convert<F> gbtowide(new F("zh_CN.gb18030"));
}