display-id
    OpenVMS usage:identifier
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Specifies the virtual display in which scrolling takes place. The
    display-id argument is the address of an unsigned longword that
    contains the display identifier.
    The display identifier is returned by SMG$CREATE_VIRTUAL_DISPLAY.
 start-row
    OpenVMS usage:longword_signed
    type:         longword (signed)
    access:       read only
    mechanism:    by reference
    Specifies the first line of the virtual scrolling region. The
    start-row argument is the address of a signed longword that
    contains the starting line number. If omitted, the first line
    of the display is used.
 end-row
    OpenVMS usage:longword_signed
    type:         longword (signed)
    access:       read only
    mechanism:    by reference
    Specifies the last line of the virtual scrolling region. The end-
    row argument is the address of a signed longword that contains
    the ending line number. If omitted, the last line of the virtual
    display is used.