To initiate and terminate key capture in a GW-BASIC program.
KEY(n) ON KEY(n) OFF KEY(n) STOP
n is a number from 1 to 20 that indicates which key is to be captured. Keys are numbered as follows:
|1-10||Function keys F1 through F10|
|15-20||Keys defined in the following format (see KEY statement): KEY n, CHR$(hex code) + CHR$(scan code)|
Execution of the KEY(n) ON statement is required to activate keystroke capture from the function keys or cursor control keys. When the KEY(n) ON statement is activated and enabled, GW-BASIC checks each new statement to see if the specified key is pressed. If so, GW-BASIC performs a GOSUB to the line number specified in the ON KEY(n) statement. An ON KEY(n) statement must precede a KEY(n) statement.
When KEY(n) OFF is executed, no key capture occurs and no keystrokes are retained.
If KEY(n) STOP is executed, no key capture occurs, but if a specified key is pressed, the keystroke is retained so that immediate keystroke capture occurs when a KEY(n) ON is executed.
For further information on key trapping, see the ON KEY(n) statement.