The following restrictions apply to programs that plan to use non-hidden attribute terminals. The restrictions are largely based on physical attributes of these terminals. In essence, by setting RESTRICTED-VIDEO-MODE
to a non-zero value, you are declaring to ACUCOBOL-GT that you are willing to work with some restrictions beyond those imposed
by other types of terminals. The end user should be aware that moving an application to this type of terminal from a normal
type may result in unexpected effects.
The following restrictions apply:
- Under the current version of ACUCOBOL-GT, this style of attribute handling may be applied only at the field and Screen Section
levels. If you are using one of these types of terminals, the REVERSED and COLOR phrases of the DISPLAY WINDOW, DISPLAY LINE,
and DISPLAY BOX verbs will be ignored.
- The Terminal Manager makes no attempt to control the screen attributes present when a window is created. If you create a pop-up
window over one-half of a reverse-video field, and then you clear that window, the reverse-video field will suddenly extend
across the screen when the terminating attribute character is erased. You should keep fields either wholly contained in a
window or wholly outside a window.
- The various RESTRICTED-VIDEO-MODE settings can interact with SCROLL and WRAP settings in unexpected ways. For example, if
you have a field wrap-around, the video attribute used for that field will also wrap around for some terminals, but not for
others. On the other hand, if you set WRAP to zero and cause a field to be truncated, then the terminating attribute character
will not be placed on the screen, and the video attribute may wrap around to the next line on some terminals. Care should
be taken with fields that wrap around or scroll the screen.
- If you position one field within another, you will affect the attributes of the characters that follow the contained field.
Keep your fields separate from each other and supply enough space between fields to hold the attribute characters.
These restrictions are relatively easy to work with until you start working extensively with windows. When working with windows,
try to keep the use of attributes to a minimum (particularly reverse-video) in order to avoid difficulties. You can use high
and low intensity or boxes to organize your screen. Just use reverse-video for special highlighting.
If you intend to use video attributes on these types of terminals, then you should make sure that you fully test your programs
on one of them.