FUNCTION CPYRTN
	LOGICAL*1 CPYRTN
C
C	The following programs are used in the RT-11 User and RT-11
C	Programmer self paced instruction courses for RT-11 V4.They are also
C	similar to programs used in the Programming with RT-11 series for
C	RT-11 V5.0 or later. The name of the files are as specified in the
C	self paced course.
C
C	The code is supplied as a service as Digital does not supply these
C	on diskette.
C	Any copyright is the property of Digital Equipment Corporartion
C
C
C FILE SBCOPY.FOR
C
C SINGLE-BUFFERED, SYNCHRONOUS COPY ROUTINE
C
C FUNCTION RETURNS .TRUE. IF AN ERROR IS ENCOUNTERED,
C RETURNS .FALSE. OTHERWISE.
C
C
	INTEGER INCHN,OUTCHN
	COMMON /CHNNLS/INCHN,OUTCHN
C
	INTEGER BUFFER(256)
	INTEGER BLOCK
C
C
	BLOCK = 0 !BLOCK NUMBER IN FILE
C
C READ/WRITE LOOP. BEGIN BY READING INTO INPUT BUFFER.
20	IERR = IREADW(256,BUFFER,BLOCK,INCHN)
	IF (IERR.GE.0) GO TO 30 !READ SUCCESSFUL
	IF (IERR.EQ.(-1)) GO TO 150 !END OF FILE IS NOT SERIOUS
	GO TO 100 !OTHER ERROR ON READ
C WRITE OUT BUFFER JUST READ IN
30	IF (IWRITW(256,BUFFER,BLOCK,OUTCHN).LT.0)
	1 GO TO 101 !WRITE ERROR
	BLOCK = BLOCK+1 !ADVANCE TO NEXT BLOCK
	GO TO 20
C
C ERROR ROUTINES
C
100	CALL PRINT('READ ERROR, COPY ABORTED')
	GO TO 140
101	CALL PRINT('WRITE ERROR, COPY ABORTED')
140	CPYRTN = .TRUE.
	RETURN
C SUCCESSFUL RETURN
150	CPYRTN = .FALSE.
	RETURN
	END