When the system encounters a DD statement with a DDNAME parameter,
it saves the ddname and, temporarily, the name in the DDNAME parameter;
the system uses the DDNAME name to relate the statement to a later
DD statement. When the system finds a statement whose ddname has been
temporarily saved, it does the following:
- It uses the parameters on the statement with the matching ddname
to define the data set.
- It associates these parameters with the name of the statement
that contained the DDNAME parameter.
- It stops saving the name from the DDNAME parameter.