Handling overflow

When a sum becomes larger than the space available for it, overflow occurs. For example, if a 2-byte binary field (unsigned) contains X' FFFF' and you add X'0001' to it, overflow occurs, because the sum requires more than two bytes.

  FFFF
  0001
 10000

If overflow occurs, the summary fields in the two records involved are not added together. That is, the records are kept unchanged; neither record is deleted.

In some cases, you can correct overflow by padding the summary fields with zeros, using the INREC control statement. Preventing overflow when summing values shows you how to do this.