On FKey

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As of 4.20 On Fnkey was renamed to On FKey OPTION 58 restores recognition of FNKEY if needed.


ON FKEY <integer> <action> 


Integer is the value of FKEY referenced.

Action is GOTO <line-ref>, SYSTEM or IGNORE.

For example:


See also On Error.

A few facts about ON FKEY.

  • ON FKEY for each of 1-49 is set to ignore by default, as per System Defaults
  • ON FKEY conditions are treated as error conditions and are checked for at the same time as Ctrl+A.
  • If the system default for an FKEY (i.e. ignore) is overridden by an ON FKEY statement then when the FKEY interrupt is triggered, either by pressing the corresponding function key or some other method, then the specified ON action is performed.
  • ON FKEY ## IGNORE can be specified to turn off special ON FKEY processing

Error 1 can be triggered by the pressing that fkey.


The following example demonstrates the use of ON FKEY. Keep in mind however, that when the operator presses an FKEY corresponding to ON FKEY, the program stops whatever it is doing and doesn't return, possibly losing data and other key information

00030     print fields "2,2,c 100": "At any time you may select F8 for main menu, F9 to print the screen, or F10 for the help menu."
00040     on fkey 8 goto MENU8 
00050     on fkey 9 goto MENU9
00060     on fkey 10 goto MENU10
03120     stop
03130  !
03140  MENU8: chain MENU
03150     stop
03160  MENU9: printscreen
03170     stop
03180  MENU10: proc helpmenu