Designing Interactive Panels (Panel Services) › Intercept Function Keys

Intercept Function Keys

By default, Panel Services intercepts certain function key actions in an identical manner to the rest of the system, as follows:

F2 or F14

Screen split operation

F3 or F15

Terminate NCL procedure

F4 or F16

Terminate NCL procedure

F9 or F21

Screen split/swap operation

While the use of these keys is transparent to NCL procedures invoking full-screen panels, this might not always be desirable. A procedure might want to intercept all function keys and invoke alternative functions.

Panel Services offers two levels of function key interception which can be requested using an &CONTROL verb, before issuing the &PANEL statement where they are to apply. To simplify processing, you can perform optional function key mapping, where F13 to F24 are mapped to their F1 to F12 counterparts.

&CONTROL PFKSTD

PFKSTD stops the interception of F3/15 and F4/16, which normally terminate the invoking NCL procedure. Using these keys returns you to the NCL procedure with the appropriate value set in the &INKEY system variable. F2/F14 and F9/F21 operate as normal, providing screen split/swap facilities.

&CONTROL PFKALL

PFKALL lets you allocate alternative functions to all Function keys, or to block screen splitting, if required. PFKALL stops all Function key interceptions and returns to the NCL procedure with the appropriate value set within &INKEY. In this case, screen split and swap facilities are not available unless your NCL procedure issues the appropriate SPLIT or SWAP command when the associated keys are pressed.

&CONTROL NOPFK

Returns PFKSTD or PFKALL to standard operation.

&CONTROL PFKMAP

This option can simplify the number of keys which a procedure must allow for.

PFKMAP maps F13 to F24 against their counterparts before presenting them to the NCL procedure in the &INKEY system variable. When this option is in effect, the procedure does not have to cater for F13 to F24 because F13 is presented as F1, F14 is presented as F2, and so on.

&CONTROL NOPFKMAP

NOPFKMAP turns off function key mapping.

Function keys are presented to the procedure unchanged, so that all function keys are available for separate uses.

Note: Terminals under EASINET control always operate as though &CONTROL PFKALL is in effect, and cannot operate in split screen mode.