std::wstring_convert<Codecvt,Elem,Wide_alloc,Byte_alloc>::to_bytes
From cppreference.com
< cpp | locale | wstring convert
| Defined in header <locale>
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| 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
Run this code
#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
See also
| converts a byte string into a wide string (public member function) | |
| converts a wide string to narrow multibyte character string, given state (function) | |
| [virtual] |
converts a string from InternT to ExternT, such as when writing to file (virtual protected member function of std::codecvt<InternT,ExternT,StateT>) |