KBDDISABLE()
 Locks/unlocks the keyboard
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 Syntax

     KBDDISABLE(<lSwitch>) --> cNull

 Argument

     <lSwitch>  Designates whether the keyboard is switched on (.T.) or
     off (.F.).

 Returns

     KBDDISABLE() always returns a null string.

 Description

     With the help of this function, the keyboard can be turned on or off.
     This allows you to prevent any user input for a specific time through
     program control (even Ctrl-Alt-Del).

 Note

     .  Be sure the program reenables the keyboard and does not leave
        it locked when the program terminates.

 Example

     Switch off the keyboard for 5 seconds:

     KBDDISABLE(.F.)        // Turn off keyboard
        INKEY(5)            // Can't be shortened by input!
     KBDDISABLE(.T.)        // Turn on keyboard