The Get Characteristics of Display Viewport routine returns the
    characteristics of the specified viewport.

    Format

      SMG$GET_VIEWPORT_CHAR  display-id [,viewport-row-start]

                             [,viewport-column-start]

                             [,viewport-number-rows]

                             [,viewport-number-columns]

1  –  Returns

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

2  –  Arguments

 display-id

    OpenVMS usage:identifier
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference

    Identifier of the virtual display associated with the viewport.
    The display-id argument is the address of an unsigned longword
    containing this identifier.

 viewport-row-start

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

    Optional argument that receives the starting row number of the
    viewport. The viewport-row-start argument is the address of a
    signed longword that receives this row number.

 viewport-column-start

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

    Optional argument that receives the starting column number of
    the specified viewport. The viewport-column-start argument is the
    address of a signed longword that receives this column number.

 viewport-number-rows

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

    Optional argument that receives the number of rows in the
    specified viewport. The viewport-number-rows argument is the
    address of a signed longword that receives this number.

 viewport-number-columns

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

    Optional argument that receives the number of columns in the
    specified viewport. The viewport-number-columns argument is the
    address of a signed longword that receives this number.