The Change Virtual Display routine lets you change the
    dimensions, border, and video attributes of a virtual display.

    Format

      SMG$CHANGE_VIRTUAL_DISPLAY  display-id [,number-of-rows]

                                  [,number-of-columns]

                                  [,display-attributes]

                                  [,video-attributes]

                                  [,character-set]

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

    Specifies the virtual display whose attributes are to be changed.
    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.

 number-of-rows

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

    Specifies the new number of rows for the virtual display. The
    number-of-rows argument is the address of a signed longword that
    contains the number of rows in the virtual display.

 number-of-columns

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

    Specifies the new number of columns for the virtual display. The
    number-of-columns argument is the address of a signed longword
    that contains the number of columns in the virtual display.

 display-attributes

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

    Specifies the attributes of the virtual display. The display-
    attributes argument is the address of a longword bit mask that
    contains the display attributes.

    Valid values for display-attributes are as follows:

    SMG$M_BORDER       Specifies a bordered display. If omitted, the
                       display is not bordered.
    SMG$M_BLOCK_       Specifies a block bordered display. If
    BORDER             omitted, the display is not bordered.
    SMG$M_DISPLAY_     Specifies that control characters such as
    CONTROLS           carriage return and line feed are displayed as
                       graphic characters, if your terminal supports
                       them.
    SMG$M_TRUNC_ICON   Specifies that an icon (generally a diamond
                       shape) is displayed where truncation of a line
                       exceeding the width of the virtual display has
                       occurred.

 video-attributes

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

    Specifies the default rendition to be applied to all output in
    a virtual display, unless overridden by a call to a specific
    output routine. The video-attributes argument is the address of
    an unsigned longword that contains the video attributes mask.

    For example, a call to SMG$PUT_CHARS with an explicit rendition
    specified would override the default rendition.

    The bits that can be set for this argument are as follows:

    SMG$M_BLINK        Displays blinking characters.
    SMG$M_BOLD         Displays characters in higher-than-normal
                       intensity.
    SMG$M_REVERSE      Displays characters in reverse video; that
                       is, to the opposite of the current default
                       rendition of the virtual display.
    SMG$M_UNDERLINE    Displays underlined characters.
    SMG$M_INVISIBLE    Specifies invisible characters; that is, the
                       characters exist in the virtual display but do
                       not appear on the pasteboard.
    SMG$M_USER1        Displays user-defined attributes.
    through
    SMG$M_USER8

    You can specify any combination of attributes in a single call.
    All other bits are reserved for use by VSI and must be 0.

 character-set

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

    Specifies the default character set for all text in this virtual
    display. The character-set argument is the address of an unsigned
    longword that contains the character set specifier. Valid values
    are SMG$C_ASCII (the default), and SMG$C_SPEC_GRAPHICS.