Converts a one-byte multibyte character to a wide character in
    the initial shift state.

    Format

      #include  <wchar.h>

      wint_t btowc  (int c);

1 - Argument

 c

    The character to be converted to a wide-character representation.

2 - Description

    The btowc function determines whether (unsigned char)c is a valid
    one-byte multibyte character in the initial shift state, and if
    so, returns a wide-character representation of that character.

3 - Return Values

    x                  The wide-character representation of unsigned
                       char c.
    WEOF               Indicates an error. The c argument has the
                       value EOF or does not constitute a valid one-
                       byte multibyte character in the initial shift
                       state.