Int 21 Fn 4456  U - Dr Dos 5.0+ - History Buffer Control                   [O]

   AX = 4456h
   DL = control flags (see #1268)

Return: AL = previous value of state flags (see #1269)

Note:  DR DOS 6.0 only checks bit 0 and ignores the rest of DL

See Also: #1270

Bitfields for control flags:
Bit(s) Description (Table 1268)
 0 whose buffer: 0=application, 1=COMMAND.COM
---Novell DOS 7---
 1 toggle HISTORY usage
 2 toggle INSERT state

Note:  only one bit at a time may be used

Bitfields for state flags:
Bit(s) Description (Table 1269)
 0 HISTORY buffer enabled
 1 INSERT enabled
 2-5   unused
 7 whose buffer: 0=application, 1=COMMAND.COM