format

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

  . . .

    Optional expressions whose results correspond to conversion
    specifications given in the format specification.

    If no conversion specifications are given, you can omit the input
    pointers. Otherwise, the function calls must have exactly as
    many input pointers as there are conversion specifications, and
    the conversion specifications must match the types of the input
    pointers.

    Conversion specifications are matched to input sources in left-
    to-right order. Excess input pointers, if any, are ignored.