qa.hlp (Table of Contents; Topic list)
Int 21H Function 06H
   Summary  Notes  Example  Back
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▀ No special action is taken upon entry of a CTRL+C when this service is
  used.
 
▀ To read extended ASCII codes (such as the special function keys F1 to
  F10) on the IBM PC and compatibles, you must call this function twice.
  The first call returns the value 00H to signal the presence of an ex-
  tended code.
 
▀ See also Int 21H Functions 01H, 07H, and 08H, which provide character
  input with various combinations of echo and/or CTRL+C sensing, and
  Functions 02H and 09H, which may be used to write characters to the
  standard output.
 
▀ You can also read the keyboard by issuing a read (Int 21H Function 3FH)
  using the predefined handle for the standard input (0000H), if input
  has not been redirected, or a handle obtained by opening the logical
  device CON.
 
▀ You can also send characters to the display by issuing a write (Int 21H
  Function 40H) using the predefined handle for the standard output
  (0001H), if output has not been redirected, or using a handle obtained
  by opening the logical device CON.
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