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Dokumentation

Length of a structure is larger than expected
Tip-No.: 2706 ( INFO2706 )

Short text

Length of a structure is larger than expected
Tip-No.: 2706

Symptom

1. The length of a structure defined in DD is larger than expected.
or
2. The length of a field header that contains a statement INCLUDE
STRUCTURE or a field of type Integer (I) or Float (F), is longer
than expected.

Cause

The structure contains at least one field of type I (integer) or
F (float).
With such structures,
1. each integer field contained in the structure is provided with a
word limit,
2. each type F field in the structure is provided with a double word
limit and
3. the total length of the structure is extended so that a multiple of
the highest alignment request of the individual fields. If a
structure contains I fields, then the total length can be divided
by 4; if the structure contains float fields, the total length can
be divided by 8.

With this, gaps can both appear within the structure (see 1 and 2)
or the structure can be extended at the end (see 3). This can lead to
the length of a structure being larger than the total of the lengths of
the individual fields.

This applies to both structures created with TABLES and program-internal
field headers created with BEGIN OF/ END OF or INCLUDE STRUCTURE.

Solution

These characteristics must be taken into account when integer
and float fields are used.