KEY(n) - DualBrain/bsharp Wiki

To initiate and terminate key capture in a GW-BASIC program.

Syntax

KEY(n) ON

KEY(n) OFF

KEY(n) STOP

Comments

n is a number from 1 to 20 that indicates which key is to be captured. Keys are numbered as follows:

Key Number Key
1-10 Function keys F1 through F10
11 CURSOR UP
12 CURSOR LEFT
13 CURSOR RIGHT
14 CURSOR DOWN
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, BASIC checks each new statement to see if the specified key is pressed. If so, 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.