Aggregates (arrays, strings, or structures) are mapped differently by C and PL/I and are not automatically mapped. Be sure to completely declare every byte in the aggregate so there are no open fields. Doing so helps ensure that the layouts of aggregates passed between the two languages map to one another correctly. The C and PL/I AGGREGATE compile-time options provide a layout of aggregates to help you perform the mapping.

For more information about PL/I structure mapping, see the appropriate language reference and programming guide.