次の例では、2 つ目の PERFORM 文の範囲の末尾によってエラーが発生しています。
$set ilshowperformoverlap
...
perform a thru c.
perform c thru b.
goback.
*> Errors are displayed as follows:
a section. *> COBCH1663E Overlapping perform range: 2 entries
display "In a". *> COBCH1664E perform range: a thru c
b section.
display "In b".
c section. *> COBCH1664E Perform range: c thru b
display "In c". *> COBCH1667E perform range end before start
go to a.