std::wstring_convert

From Cppreference

Jump to: navigation, search

Defined in header `<locale>`

template< class Codecvt, class Elem = wchar_t, class Wide_alloc = std::allocator<Elem>, class Byte_alloc = std::allocator<char> > class wstring_convert;		(C++11 feature)

Class template std::wstring_convert performs conversions between byte string std::string and wide string std::basic_string<Elem>, using an individual code conversion facet Codecvt. std::wstring_convert assumes ownership of the conversion facet, and cannot use a facet managed by a locale. The standard facets suitable for use with std::wstring_convert are std::codecvt_utf8 for UTF-8/UCS2 and UTF-8/UCS4 conversions and std::codecvt_utf8_utf16 for UTF-8/UTF-16 conversions.

#include <iostream>
#include <string>
#include <locale>
#include <codecvt>
int main()
{
    // UTF-8 data: letter 'z', CJK ideogram 'water', musical sign 'segno'
    std::string utf8 = u8"z\u6c34\U0001d10b";
 
    // the UTF-8 / UTF-16 standard conversion facet
    std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> utf16conv;
    std::u16string utf16 = utf16conv.from_bytes(utf8);
    std::cout << "UTF16 conversion produced " << utf16.size() << " code points:\n";
    for(char16_t c : utf16)
        std::cout << std::hex << std::showbase << c << '\n';
 
    // the UTF-8 / UTF-32 standard conversion facet
    std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> utf32conv;
    std::u32string utf32 = utf32conv.from_bytes(utf8);
    std::cout << "UTF32 conversion produced " << std::dec << utf32.size() << " code points:\n";
    for(char32_t c : utf32)
        std::cout << std::hex << std::showbase << c << '\n';
}

Output:

UTF16 conversion produced 4 code points:
0x7a
0x6c34
0xd834
0xdd0b
UTF32 conversion produced 3 code points:
0x7a
0x6c34
0x1d10b

[edit] See also

Character conversions	narrow multibyte (char)	UTF-8 (char)	UTF-16 (char16_t)
UTF-16	`mbrtoc16` / `c16rtombr`	`codecvt`<char16_t, char, mbstate_t> `codecvt_utf8_utf16`<char16_t> `codecvt_utf8_utf16`<char32_t> `codecvt_utf8_utf16`<wchar_t>	N/A
UCS2	No	`codecvt_utf8`<char16_t>	`codecvt_utf16`<char16_t>
UTF-32/UCS4 (char32_t)	`mbrtoc32` / `c32rtombr`	`codecvt`<char32_t, char, mbstate_t> `codecvt_utf8`<char32_t>	`codecvt_utf16`<char32_t>
UCS2/UCS4 (wchar_t)	No	`codecvt_utf8`<wchar_t>	`codecvt_utf16`<wchar_t>
wide (wchar_t)	`codecvt`<wchar_t, char, mbstate_t> `mbstowcs` / `wcstombs`	No	No

wbuffer_convert (C++11)

performs conversion between a byte stream buffer and a wide stream buffer
(class template)

codecvt_utf8 (C++11)

converts between UTF-8 and UCS2/UCS4
(class template)

codecvt_utf8_utf16 (C++11)

converts between UTF-8 and UTF-16
(class template)


Member type	Definition

`byte_string`	`std::basic_string<char, char_traits<char>, Byte_alloc>`

`wide_string`	`std::basic_string<Elem, char_traits<Elem>, Wide_alloc>`

`state_type`	`Codecvt::state_type`

`int_type`	`wide_string::traits_type::int_type`

std::wstring_convert

From Cppreference

Contents

[edit] Member types

[edit] Member functions

[edit] Example

[edit] See also