INT 21 - DOS 2+ - IOCTL - WRITE TO CHARACTER DEVICE CONTROL CHANNEL
AX = 4403h
BX = file handle referencing character device
CX = number of bytes to write
DS:DX -> data to write
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see #01680 at AH=59h/BX=0000h)
Notes: format of data is driver-specific
(also see separate entries below for some specific cases)
if the file handle refers to "4DOSSTAK", the 4DOS (v2.x-3.03)
KEYSTACK.SYS driver will push the specified characters on the
keyboard stack; similarly for "NDOSSTAK", the NDOS KEYSTACK.SYS
driver will push the characters onto the keyboard stack
this function was not supported by Digital Research's DOS Plus
SeeAlso: AX=4400h,AX=4402h"DOS 2+",AX=4405h"DOS",INT 2F/AX=122Bh
SeeAlso: INT 2F/AX=D44Dh,INT 2F/AX=D44Fh