Procedure NTABT	(
	Lun: Integer;
	efn: Event_flag;
	msg: CH16;
	VAR IOSB: IO_Status_block
		);
   EXTERNAL;
{*USER*
 
Immediately abort specified logical link. All pending traffic on the
link is killed, and the LUN freed.
 
EFN is required (do NOT use f0), and is set when the abort completes
(will be set upon return).
 
MSG is an optional user data string which is sent to the other end
of the link as part of the disconnect message. It may be of zero length
(in-use length). It is recommended that an empty type-0 string be used
if no user message is desired.
 
Control returns when the abort completes.
 }