file_ptr

    A file pointer.

 buffer

    A pointer to a character string that is large enough to hold the
    file specification.

  . . .

    An optional additional argument that can be either 1 or 0. If you
    specify 1, the fgetname function returns the file specification
    in OpenVMS format. If you specify 0, fgetname returns the file
    specification in UNIX style format. If you do not specify this
    argument, fgetname returns the filename according to your current
    command language interpreter.