AT&T 6300 Programmer's Manual page 253

Example
ERR and ERL
Functions
To test whether an error occurred in a direct
statement, use IF 65535=ERL THEN _
Otherwise, use
IF ERR=error code THEN_
IF ERL=line number THEN_
LIST
10 REMRECTANGLE2
20 ON ERROR GOlO 70
30 INPUT ULength and Width";L,W
40 IF (L < 0) OR (W < 0) THEN ERROR 200
50
PRINT uArea = ';L *W;" L = ';L;" W = ';W
60 G010 30
70 IF (ERR = 200) AND (ERL = 40)
THEN PRINT uL or W < O':RESUME 30
80
ON ERROR GOTO 0
90 END
Ok
RUN
Length and Width?
-2,5
Lor W<O
Length and Width?
2,5
Area= 10L = 2W= 5
Length and Width?
C
Break in 30
Ok
7-97