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(48) Implementation-defined components.
Implementation-defined components are created for the following purposes:
- An implementation-defined component is generated for the tag of a tagged record. The tag is a single 32-bit value stored at offset 0 in the record.
- An implementation-defined component is generated for each discriminant-dependent component in the record to indicate the offset to the component. Each offset is a single 32-bit value stored in the record immediately following fixed layout portion of the record.
These implementation-defined components have no names and therefore cannot used in record_representation_clauses.