std::wctob (3) - Linux Manuals

std::wctob: std::wctob


std::wctob - std::wctob


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

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


// Run this code

  #include <clocale>
  #include <cwchar>
  #include <iostream>

  void try_narrowing(wchar_t c)
      int cn = std::wctob(c);
      if(cn != EOF)
          std::cout << '\'' << c << "' narrowed to " << +cn << '\n';
          std::cout << '\'' << 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";

      std::setlocale(LC_ALL, "th_TH.tis620");
      std::cout << "In Thai TIS-620 locale:\n";


  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

See also

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