std::wctob (3) - Linux Man Pages
Defined in header <cwchar>
int wctob( std::wint_t c );
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.
c - wide character to narrow
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
// Run this code
narrow (public member function of std::basic_ios<CharT,Traits>)
narrow (public member function of std::ctype<CharT>)