Reads input from the stream under control of the wide-character
    format string.

    Format

      #include  <wchar.h>

      int vswscanf  (wchar_t *s, const wchar_t *format, va_list ap);

1 - Arguments

 s

    A pointer to a wide-character string from which the input is to
    be obtained.

 format

    A pointer to a wide-character string containing the format
    specifications.

 ap

    A list of expressions whose results correspond to conversion
    specifications given in the format specification.

2 - Description

    The vswscanf function is equivalent to the swscanf function,
    except that instead of being called with a variable number of
    arguments, it is called with an argument list (ap) that has been
    initialized by va_start (and possibly with subsequent va_arg
    calls).

    The vswscanf function is also equivalent to the vfwscanf
    function, except that the first argument specifies a wide-
    character string rather than a stream. Reaching the end of the
    wide-character string is the same as encountering EOF for the
    vfwscanf function.

    For more information about format and conversion specifications
    and their corresponding arguments, see the "Understanding Input
    and Output" chapter of the HP C RTL Reference Manual.

    See also vfwscanf and swscanf.

3 - Return Values

    n                  The number of wide characters read.
    EOF                Indicates that a read error occurred before
                       any conversion. The function sets errno. For a
                       list of the values set by this function, see
                       vfscanf.