directory-spec1
    Specifies the directory specification of the Version 2.0 or 3.1
    library to be converted.

 directory-spec2
    Specifies the directory in which the Version 4.0 library is to be
    created. If this parameter is omitted, the new library is created
    in the directory specified by directory-spec1, and the old library
    is deleted. If this parameter is specified and is different from
    directory-spec1, the old library is not deleted.