Xbase++ - Command CLEAR TYPEAHEAD

Deletes all characters from the keyboard buffer or the event queue.

CLEAR TYPEAHEAD

The command CLEAR TYPEAHEAD deletes all characters currently found in the keyboard buffer or event queue, respecively. The command is generally used before calling functions which independently react to keyboard input. This includes functions like AChoice(), DbEdit() or MemoEdit(). In such cases, CLEAR TYPEAHEAD guarantees that no key codes or events are already waiting for processing.

The keyboard buffer can also be erased using the commands SET TYPEAHEAD and KEYBOARD.

CLEAR TYPEAHEAD

// In the example, characters are written into the keyboard 
// buffer. To keep these characters from being processed 
// by MemoEdit(), the command CLEAR TYPEAHEAD erases the 
// keyboard buffer before the call to MemoEdit() 

PROCEDURE Main 
   LOCAL cText := "" 

   KEYBOARD "Xbase++" 
   ? NextKey()                      // result: 88 
   ? Chr( NextKey() )               // result: X 

   CLEAR TYPEAHEAD 
   ? NextKey()                      // result: 0 

   cText := MemoEdit(cText) 

RETURN

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Command CLEAR TYPEAHEAD Foundation