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I/O statement
KEY ON and KEY OFF
Enables or disables keystroke trapping for a specified function key.
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Syntax:
Syntax:Syntax:
Syntax:
KEY (keynumber){ON|OFF}
Parameter:
Parameter:Parameter:
Parameter:
keynumber
A numeric expression which returns a value from 1 to 31 and 33 to 38.
Description:
Description:Description:
Description:
KEY ON
KEY ON enables keystroke trapping for a function key specified by keynumber. (Refer to
Appendix E, "Key Number Assignment on the Keyboard.")
• Between every execution of statements, the Interpreter checks whether a function key
specified by the KEY ON statement is pressed or not. If the key is pressed, the Interpreter
transfers control to the event-handling routine defined by an ON KEY ..GOSUB statement
(which should be executed before the KEY ON statement).
• If a function key which has been assigned a null string by the KEY statement is
specified by the KEY ON statement, the keystroke trap takes place.
• If you specify a function key which has been defined as a backlight function on/off key,
trigger switch, shift key, or software keyboard display key by using the KEY ON statement,
then no keystroke trap takes place.
• Keystroke trapping has priority over the INKEY$ function.
• When a program waits for the keyboard entry by the INPUT, LINE INPUT statement or
INPUT$ function, pressing a function key specified by the KEY ON statement neither
reads the pressed key data nor causes keystroke trapping.
• Specifying 32 to keynumber will be ignored.
KEY OFF
KEY OFF disables keystroke trapping for a function key specified by keynumber.
• Specifying 32 to keynumber will be ignored.
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