Procedure NTSPA (
	lun: Integer;
	EFN: Event_flag;
	VAR IOSB: IO_Status_block
	);
   EXTERNAL;
{*USER*
 
This routine uses the SPA$ routine to set up a network data AST. The
AST routine executes each time data is posted to the task network
data queue (Network Mailbox).  For the Pascal environment, the AST
routine is hidden here, and only sets the specified event flag.
 
LUN specifies the network queue LUN (the one used in NTOPN).
 
To disable AST service, call NTSPA with a null event flag (f0).
 
Upon return, IOSB[2] contains the number of pending network data
messages (assuming IOSB[1]=1). NTSPA may be called repeatedly to
determine this number. NTSPA may be called with f0, resulting
in no AST service, but still returning the data count.
 
NOTE: Because it contains the AST service routine, and local storage
for the EFN, this module may not be placed in an overlay segment or
resident library.
 
 }