Screen-labeled function key descriptors

Eight labels appear on the last line of the user's screen to indicate the functions currently assigned to the corresponding keyboard function keys <F1> through <F8>. The screen labels are analogous to a set of menu items that are always displayed and from which the user can make a selection at any time by pressing the corresponding function key. If a keyboard does not have function keys, the user can select the function by using one of the alternative keystroke sequences <CTRL-f> <1> through <CTRL-f> <8>.

FMLI provides two sets of screen labels for function keys. There are eight screen labels in each set. FMLI has preassigned functions to only the first set of eight for each frame type.

Default Screen-labeled Keys

Function key	Menu frame	Form frame	Text frame	Choices menu	Command menu
<F1>	help	help	help		help
<F2>	mark*	choices	prevpage
<F3>	enter	save	nextpage	enter
<F4>	prev-frm	prev-frm	prev-frm
<F5>	next-frm	next-frm	next-frm
<F6>	cancel	cancel	cancel	cancel	cancel
<F7>	cmd-menu	cmd-menu	cmd-menu
<F8>	chg-keys**	chg-keys**	chg-keys**	chg-keys**	chg-keys**
<F16>	chg-keys**	chg-keys**	chg-keys**	chg-keys**	chg-keys**

*

Function key <F2> is assigned the mark command only in multi-select menus. In single-select menus <F2> has no default assigned.

**

Function keys <F8> and <F16> will default to chg-keys only if any of keys <F9> through <F15> are defined by the developer.

Function keys <F1> through <F7> in the first set can be disabled but not redefined. Function keys <F8> through <F16> may be defined. However, if you define <F8> or <F16>, the user loses the ability to alternate between the two sets of SLKs. If you want to define PREV-FRM, NEXT-FRM, PREVPAGE, or NEXTPAGE, on the second set of function keys, the labels must be spelled exactly as they are on the first set (case is irrelevant).

You can define which set of screen-labeled function keys first appears when a frame is opened by defining the frame level descriptor altslks in menu, text, and form definition files. If altslks evaluates to TRUE, the screen labels for function keys 9 through 16 will be displayed when the frame is first opened.

The following is a list of the descriptors used to define screen-labeled function keys. The name and button descriptors must be included in each set of SLK descriptors, and name must be first.

action

The action descriptor defines the command to execute when the particular screen-labeled function key is selected.

button

The button descriptor specifies the screen-labeled function key you are defining or disabling. The value of button is an integer corresponding to the number of the function key (1 through 16) to which the screen label corresponds.

interrupt

The interrupt descriptor defines whether an executable that is coded in the action descriptor can be interrupted by the user. If not coded, interrupt defaults to FALSE. If this descriptor evaluates to TRUE, then executables will be interruptible.

If the interrupt descriptor is defined for a SLK in the initialization file, that value is inherited by the SLK unless the SLK is redefined in a frame definition file. Redefining a SLK in a frame definition file completely overrides a definition of it you may have coded in the initialization file. For example, if you define interrupt for a particular SLK in the initialization file, but do not include interrupt in a redefinition of that SLK in a frame definition file, the SLK will inherit the value of the interrupt descriptor defined at the next higher inheritance level (from the frame descriptors if defined there, then from the general descriptors in the initialization file if defined there, then from the FMLI defaults).

name

The name descriptor defines the name that is displayed on the screen label. The value of name must be 8 or fewer characters. Defining name as a null string (name="") will disable the function key.

oninterrupt

The oninterrupt descriptor specifies the action to be taken when an interrupt signal is received. If it is not defined anywhere in your application, it defaults to `message Operation interrupted!`nop. It is ignored if interrupt is not coded anywhere in your application or if interrupt evaluates to FALSE.

If the oninterrupt descriptor is defined for a SLK in the initialization file, that value is current for the SLK, unless the SLK is redefined in a frame definition file. If a SLK is redefined in a frame definition file, all descriptors for that SLK in the initialization file, including the oninterrupt descriptor, are ignored. If a SLK definition does not define oninterrupt, the SLK inherits the value set for oninterrupt from the frame level descriptors, then from the application level section of the initialization file.

Example definitions of screen-labeled function keys

The following example shows how to

• disable <F7> (labeled <CMD-MENU> and assigned the FMLI command cmd-menu by default)

• define <F9> (the first SLK in set 2) to execute the exit command and display the screen label <EXIT>