Creating Windows Creating Windows eV+ communicates to windows through logical units, with logical unit numbers (LUNs) 20 to 23 reserved for window use. (Each task has access to its own set of four LUNs.) The basic strategy for using a window (or any of the graphics instructions) is: 1. ATTACH to a logical unit 2. FOPEN a window on the logical unit 3. Perform the window's tasks (or graphics operations) 4. FCLOSE the window 5. FDELETE the window 6. DETACH from the logical unit ATTACH Instruction The ATTACH instruction sets up a communications path so a window can be written to and read from. The syntax for the ATTACH instruction is:
ATTACH (glun, 4) "GRAPHICS" glun variable that receives the number of the attached graphics logical unit. (All menus and graphics commands that take place within a window will also use glun.) FOPEN Instruction FOPEN creates a new window or reselects an existing window for input and output. When a window is created, its name is placed in the list of available windows displayed when the adept logo is clicked on. The simplified syntax for FOPEN is: FOPEN (glun) "window_name /MAXSIZE width height" glun The logical unit already ATTACHed to. window_ name The title that appears at the top of the window. Also used to close and select the window.
width/height Specify the largest size the window can be opened to. This instruction will give you a window with all the default attributes. See the description of FOPEN and FSET in the eV+ Language Reference Guide for details on how to control the attributes of a window e6 for example, background color, size, and scrolling. eV+Language User's Guide, v2.x, 18318-000 Rev A Page 162