/FUNCTION[=Keyword]

 	This qualifier specifies for which I/O function the watchpoint is set.

 	An optional keyword may be given:

 	FUNCTION=ALL		The watchpoint is set for all I/O functions

 	FUNCTION=READ		The watchpoint is set for IO$_READPBLK

 	FUNCTION=WRITE		The watchpoint is set for IO$_WRITEPBLK

 	FUNCTION=CODE=number	The watchpoint is set for the specified
 				I/O function code

 	The default is /FUNCTION=READ