.title	readf
;+
;	integer function readf(buf, n, int)
;
;	character buf(n)
;	integer n, int
;
;	this routine reads the next n bytes, or the number of bytes in the
;	next record.  It returns as its value the number of bytes
;	actually read
;
;	If an error occurs or an EOF is sensed, EOF is returned.
;
ap=%5
buf=2
n=4
int=6
	.mcall	get$
	.psect	$r.roi,con,ro,rel,lcl,i
	.enabl	lsb
readf::
	mov	@int(ap),r0		; ratfor unit number
	call	r$gfbk			; get RFDB address into r1
	bcs	10$			; c set => invalid unit
	bit	#rf.clo,(r1)		; is the file open?
	bne	10$			; NO
	get$	r.fdb(r1),buf(ap),@n(ap)	; read the next record
	bcs	10$			; c set => error
	mov	f.nrbd(r0),r0		; return number of bytes read
	return
10$:
	mov	#eof,r0			; return(EOF)
	return
	.end