The replace call

A replace operation can be done only on that portion of a concatenated segment to which an application program is data sensitive.

If no data is changed in a segment, no data is replaced. Therefore, no replace rule is violated. The replace rule is not checked for a segment that is part of a concatenated segment but is not retrieved.

For all DL/I calls, either an error is detected and an error status code returned (in which case no data is changed), or the required changes are made to all segments affected by the call. Therefore, if the required function cannot be performed for both parts of the concatenated segment, an error status code is returned, and no change is made to either the logical child or the destination parent.