Designing Interactive Panels (Panel Services) › Panel Design › Control How Long a Panel is Displayed

Control How Long a Panel is Displayed

Panels do not always have to accept operator input, although this is the most common mode of operation. NCL interfaces to other system components allow you to set up monitoring functions with display-only panels requiring little or no operator entry.

Alternatively, you might want an NCL procedure to resume control if no input is received within a certain time.

By default, whenever a synchronous panel is displayed, Panel Services waits indefinitely for entry from an operator. However, the INWAIT operand of the #OPT control statement lets you override this.

INWAIT lets you specify a time (in seconds or parts of seconds) for Panel Services to wait before control is returned to the invoking NCL procedure. During this interval, standard keyboard entry is accepted and processed normally. Once the time interval expires, control returns to the invoking NCL procedure.

This facility has many applications. For example:

• If a panel displays many high-intensity fields for long periods, you can get screen burnout. Use INWAIT to force a return of control after 20 minutes (for example), when a blank panel replaces the display panel. The original panel can be redisplayed when any input is received.
• If you specify INWAIT=0, keyboard entry is not accepted and control returns to the NCL procedure once the panel is displayed. This could be useful for displaying a message while the NCL processes the last user request.

For more information about the format of the INWAIT operand, see the #OPT statement description in the reference section.

Note: The INWAIT function does not apply to asynchronous panel operations.