std::wstring_convert<Codecvt,Elem,Wide_alloc,Byte_alloc>::to_bytes

Defined in header `<locale>`
byte_string to_bytes( Elem wchar );	(1)
byte_string to_bytes( const Elem* wptr );	(2)
byte_string to_bytes( const wide_string& wstr );	(3)
byte_string to_bytes( const Elem* first, const Elem* last );	(4)

Converts a wide sequence to a byte string using the facet pointed to by cvtptr .

1) The wide sequence only consists of one element byte.

2) The wide sequence is the null-terminated sequence beginning at ptr.

3) The wide sequence is the sequence contained in str.

4) The wide sequence is the range [first, last).

Before the conversion begins, if *this was not constructed with constructor overload (3), cvtstate will be set to its default value (the initial conversion state).

The number of input elements successfully converted will be stored in cvtcount .

Return value

If the conversion succeeds, returns the conversion result. Otherwise, if *this is constructed with constructor overload (4), returns byte_err_string.

Exceptions

If the conversion fails and *this was not constructed with constructor overload (4), throws std::range_error.

Example

#include <codecvt>
#include <iomanip>
#include <iostream>
#include <locale>
#include <string>

// utility function for output
void hex_print(const std::string& s)
{
    std::cout << std::hex << std::setfill('0');
    for (unsigned char c : s)
        std::cout << std::setw(2) << static_cast<int>(c) << ' ';
    std::cout << std::dec << '\n';
}

int main()
{
    // wide character data
    std::wstring wstr = L"z\u00df\u6c34\U0001f34c"; // or L"zß水🍌"
    
    // wide to UTF-8
    std::wstring_convert<std::codecvt_utf8<wchar_t>> conv1;
    std::string u8str = conv1.to_bytes(wstr);
    std::cout << "UTF-8 conversion produced " << u8str.size() << " bytes:\n";
    hex_print(u8str);
    
    // wide to UTF-16le
    std::wstring_convert<std::codecvt_utf16<wchar_t, 0x10ffff, std::little_endian>> conv2;
    std::string u16str = conv2.to_bytes(wstr);
    std::cout << "UTF-16le conversion produced " << u16str.size() << " bytes:\n";
    hex_print(u16str);
}

Output:

UTF-8 conversion produced 10 bytes:
7a c3 9f e6 b0 b4 f0 9f 8d 8c 
UTF-16le conversion produced 10 bytes:
7a 00 df 00 34 6c 3c d8 4c df

from_bytes	converts a byte string into a wide string (public member function)
wcsrtombs	converts a wide string to narrow multibyte character string, given state (function)
do_out [virtual]	converts a string from `InternT` to `ExternT`, such as when writing to file (virtual protected member function of `std::codecvt<InternT,ExternT,StateT>`)

std::wstring_convert<Codecvt,Elem,Wide_alloc,Byte_alloc>::to_bytes

Return value

Exceptions

Example

See also