VMS Help RTL Routines, LIB$, LIB$LP_LINES, Returns  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    OpenVMS usage:longword_signed
    type:         longword integer (signed)
    access:       write only
    mechanism:    by value

    The default number of lines on a physical printer page. If the
    logical name translation or conversion to binary fails, a default
    value of 66 is returned.