INT 15 - TopViewTopView, DESQview, TaskView, OmniView, other compatibles - SEND MESSAGE - "SETESC" - SET ESCAPE ROUTINE ADDRESS
	AH = 12h
	BH = 14h
	BL = message modifier
	    00h handle is DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. on top of stack
	    01h define user stream
	    04h intercept keystrokes from KEYBOARD to window (handle on stack)
	    05h intercept keystrokes from task's default KEYBOARD to a window
	STACK: (if window)   DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. user stream number (14h-1Fh)
			     DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. address of FAR user stream handler
	       (if keyboard) DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. address of FAR filter function (see #00452)
Return: STACK popped


(Table 00452)
Values keyboard filter function is called with when keyboard is in field mode:
	AL = character
	AH = 00h or extended ASCII code if AL = 00h
	BL = field number
	CH = cursor column
	CL = cursor row
	DL = field type modifier (sixth item in field table entry)
	DH = seventh item in field table entry
	ES:SI = window's handle
	DS:DI -> field table entry for field containing the cursor
Return: AH = action to take
	    00h use keystroke
	    01h ignore keystroke
	    FFh beep and ignore keystroke
Note: the filter function is not allowed to make INT 15, DOS, or BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. calls
                                                                                

INT 15 - TopViewTopView, DESQview, TaskView, OmniView, other compatibles - SEND MESSAGE - "LOCK" - REQUEST EXCLUSIVE ACCESS TO RESOURCE
	AH = 12h
	BH = 14h
	BL = object
	    00h mailbox handle is DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. on top of stack
	    02h use given task's mailbox (task's handle on top of stack)
	    03h use current task's default mailbox
Return: STACK popped if BL=00h
Note:	release exclusive access by sending CLOSE message to mailbox
	access may be requested multiple times, and requires multiple CLOSEs
SeeAlso: AH=12h/BH=0Dh