Reads formatted input based on an argument list.

    Format

      #include  <stdio.h>

      int vsscanf  (char *str, const char *format, va_list ap);

1 - Arguments

 str

    The address of the character string that provides the input text
    to sscanf.

 format

    A pointer to a character string that contains the format
    specification.

 ap

    A list of expressions whose resultant types correspond to the
    conversion specifications given in the format specifications.

2 - Description

    The vsscanf function is the same as the sscanf function except
    that instead of being called with a variable number of arguments,
    it is called with an argument list that has been initialized by
    va_start (and possibly with subsequent va_arg calls).

    The vsscanf function is also equivalent to the vfscanf 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 vfscanf 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 vsscanf and sscanf.

3 - Return Values

    n                  The number of successfully matched and
                       assigned input items.
    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.