The Create Virtual Display routine creates a virtual display and
    returns its assigned display identifier.

    Format

      SMG$CREATE_VIRTUAL_DISPLAY  number-of-rows ,number-of-columns

                                  ,display-id [,display-attributes]

                                  [,video-attributes]

                                  [,character-set]

1  –  Returns

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

2  –  Arguments

 number-of-rows

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

    Specifies the number of rows in the newly created virtual
    display. The number-of-rows argument is the address of a signed
    longword that contains the desired number of rows.

 number-of-columns

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

    Specifies the number of columns in the newly created virtual
    display. The number-of-columns argument is the address of a
    signed longword that contains the desired number of columns.

 display-id

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

    Receives the display-id of the newly created virtual display. The
    display-id argument is the address of an unsigned longword into
    which is written the display identifier.

 display-attributes

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

    Receives the current default display attributes. The optional
    display-attributes argument is the address of an unsigned
    longword into which the current display attributes are written.

    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_PROTECT_     Instructs the Screen Management Facility
    DISPLAY            to return an error (SMG$_DSPIN_USE) if an
                       SMG$ call is made from an AST routine that
                       interrupted an SMG$ call on the same display.
    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
    this virtual display unless overridden by a call to a specific
    output routine (for example, SMG$CHANGE_RENDITION). The video-
    attributes argument is the address of an unsigned longword that
    contains the video attributes mask.

    Valid values for this argument are as follows:

    SMG$M_BLINK        Displays blinking characters.
    SMG$M_BOLD         Displays characters in higher-than-normal
                       intensity.
    SMG$M_REVERSE      Displays characters in reverse video, that is,
                       using the opposite of the default rendition of
                       the virtual display.
    SMG$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

 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.