Procedure QIOWAL(LUN:Integer; 
		EFN:Event_flag;
		Stadd:Address; 
		Size:Integer
		);EXTERNAL;

{*USER*
 Pascal-3 Procedure to execute QIO WAL function.

This procedure will use Executive Queue I/O Request and Wait (QIOW$C) Call.  

LUN is the logical unit number to be assigned to the appropriate device.  

EFN is the event flag to be set when the I/O is completed. f0 may 
not be specified. 

STADD is the starting address of the buffer to be read or written.  
Use LOOPHOLE(Address,Ref(string)) to produce this parameter.

SIZE is the size of the buffer referenced by STADD.

Directive status is available in $DSW on return.

}