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Determining Data Object Distances

The example demonstrates how the distance between two data objects can be determined at runtime.

Other versions: 7.31 | 7.40 | 7.54

Source Code

    DATA: BEGIN OF struc,
            comp1 TYPE i,
            comp2 TYPE x LENGTH 1,
            comp3 TYPE c LENGTH 4 VALUE 'Hey',
            comp4 TYPE c LENGTH 4 VALUE 'you!',
            comp5 TYPE x,
          END OF struc.

    DATA: off TYPE i,
          len TYPE i.

    FIELD-SYMBOLS: <hex>    TYPE x,
                   <result> TYPE c.

    DESCRIBE DISTANCE BETWEEN:
             struc       AND struc-comp3 INTO off IN BYTE MODE,
             struc-comp3 AND struc-comp5 INTO len IN BYTE MODE.

    ASSIGN: struc TO <hex> CASTING,
            <hex>+off(len) TO <result> CASTING.

    WRITE: / 'Offset off is', off,
           / 'Length len is', len,
           / '<result> points to', <result>.

Description

Determining the offset and length, in bytes, of a character-like fragment within the struc structure, access to the fragment using an offset/length access and assignment to a field symbol of type c. Since the structure is not purely character-like, the offset/length access takes place using a field symbol, otherwise a syntax error occurs in a Unicode program. The field symbol is of the type x, since offset and length are determined in bytes. In Unicode systems, a different value is identified for off than in non-Unicode systems because of the alignment gap before comp3. The <result> field symbol has the same content in both cases "Hey you!".