win

    A pointer to the window.

 format_spec

    A pointer to the format specification string.

  . . .

    Optional expressions that are pointers to objects whose resultant
    types correspond to conversion specifications given in the format
    specification. If no conversion specifications are given, you may
    omit these input pointers.

    Otherwise, the function call must have at least 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.