std::wctob - cppreference.com (original) (raw)

Narrows a wide character c if its multibyte character equivalent in the initial shift state is a single byte.

This is typically possible for the characters from the ASCII character set, since most multibyte encodings (such as UTF-8) use single bytes to encode those characters.

[edit] Parameters

[edit] Return value

EOF if c does not represent a multibyte character with length 1 in initial shift state.

Otherwise, the single-byte representation of c as unsigned char converted to int.

[edit] Example

#include #include #include   void try_narrowing(wchar_t c) { int cn = std::wctob(c); if (cn != EOF) std::cout << ''' << int(c) << "' narrowed to " << +cn << '\n'; else std::cout << ''' << int(c) << "' could not be narrowed\n"; }   int main() { std::setlocale(LC_ALL, "th_TH.utf8"); std::cout << std::hex << std::showbase << "In Thai UTF-8 locale:\n"; try_narrowing(L'a'); try_narrowing(L'๛');   std::setlocale(LC_ALL, "th_TH.tis620"); std::cout << "In Thai TIS-620 locale:\n"; try_narrowing(L'a'); try_narrowing(L'๛'); }

Output:

In Thai UTF-8 locale: '0x61' narrowed to 0x61 '0xe5b' could not be narrowed In Thai TIS-620 locale: '0x61' narrowed to 0x61 '0xe5b' narrowed to 0xfb

[edit] See also

| | widens a single-byte narrow character to wide character, if possible (function) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | | narrows characters (public member function of std::basic_ios<CharT,Traits>) [edit] | | | invokes do_narrow (public member function of std::ctype) [edit] | | |