With the RCODE-INFO handle, the DISPLAY-TYPE attribute holds a value of "GUI" for a graphical display, "TTY" for a character-mode display, or a blank string ("") for code that does not contain any display-specific statements. Use of this attribute allows developers to determine if the r-code contains statements that make it executable only in the same display environment on which it was compiled. If r-code contains ABL statements that interact with the UI (such as DISPLAY), it can only be executed in the same UI. The same restriction does not apply to r-code that does not contain UI-specific statements.
With the SESSION handle, the DISPLAY-TYPE attribute holds a value of "GUI" for a graphical display or "TTY" for a character-mode display, depending on the display type of the running session.