ACUCOBOL-GT Window Types

ACUCOBOL-GT includes two fundamental window types: floating windows and subwindows (sometimes referred to as pop-up windows). Each window type is discussed briefly below. Floating windows are discussed in detail in Floating Windows.

ACUCOBOL-GT also supports many types of controls (technically a type of window). Controls are discussed in detail in Graphical Controls.

Floating Windows

A floating window is the ACUCOBOL-GT window type that creates a host-based, pop-up window. When your application executes in a graphical environment, such as Microsoft Windows, floating windows are created as native pop-up windows, managed by the host operating system and the ACUCOBOL-GT run-time.

Floating windows must be used when you want to include graphical controls, such as buttons, entry boxes, and scroll bars. ACUCOBOL-GT supports two types of floating windows: modal and modeless.

Floating windows are positioned and displayed on the virtual screen. The virtual screen is intrinsic to all applications that use floating or subwindows. The virtual screen size can be set with the SCREEN SIZE run-time configuration variable and changed during program execution with the MODIFY Statement. The default virtual screen size is 25 rows by 80 columns. See Windowing Concepts for more information.

Independent Windows

An independent window is similar to a floating window, except that independent windows do not belong to parent windows; independent windows are controlled independently.


Subwindow is the name given to ACUCOBOL-GT text-mode windows created with the DISPLAY WINDOW or DISPLAY SUBWINDOW statement.

Subwindows are always text-mode windows and are not compatible with graphical controls. However, subwindows can be mixed with floating windows, so long as the subwindows do not display on top of graphical controls. When an overlay occurs, due to the workings of the underlying host system, control objects are improperly displayed on top of the text-mode subwindow. For a discussion of textual and graphical modes, see Graphical vs Textual Modes.

You can easily convert subwindows to floating windows by changing the DISPLAY WINDOW statement to a DISPLAY FLOATING WINDOW statement. However, subwindows that simply define a screen region, that are not bordered, or are not pop-up in nature, do not lend themselves to conversion to floating windows.