Difference between revisions of "cpp/locale/codecvt"

Revision as of 10:43, 12 October 2012

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Class std::codecvt encapsulates conversion of character strings, including wide and multibyte, from one encoding to another. All file I/O operations performed through std::basic_fstream<CharT> use the std::codecvt<CharT, char, std::mbstate_t> facet of the locale imbued in the stream.

Inheritance diagram

Four specializations are provided by the standard library and are implemented by all locale objects created in a C++ program:

Member types

Member objects

Member functions

Protected member functions

Example

#include <iostream>
#include <fstream>
#include <string>
#include <locale>
#include <iomanip>
int main()
{
    // UTF-8 narrow multibyte encoding
    std::ofstream("text.txt") << u8"z\u00df\u6c34\U0001d10b"; // or u8"zß水𝄋"
                                           // or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b";
    std::wifstream fin("text.txt");
    fin.imbue(std::locale("en_US.UTF-8")); // this locale's codecvt<wchar_t, char, mbstate_t>
                                           // converts UTF-8 to UCS4
    std::cout << "The UTF-8 file contains the following wide characters: \n";
    for(wchar_t c; fin >> c; )
        std::cout << "U+" << std::hex << std::setw(4) << std::setfill('0') << c << '\n';
}

The UTF-8 file contains the following wide characters:
U+007a
U+00df
U+6c34
U+1d10b

See also