Structured field lengths

All structured fields have a minimum length of 8 bytes (for the structured field introducer). The length can be fixed-length or variable-length.

Fixed-length:
The structured field has one of two length values: 8 when there is no data or the defined maximum length. For example, if the length is defined as X'000C' (decimal 12) for a particular structured field, the length in the structured field introducer has a value of either X'0008' (no data) or X'000C' (data length = 4).
Variable-length:
The structured field can have a length that varies from 8 (no data) up to maximum stated size. For example, because a data set name varies from 1 to 44 characters in length, the length value in a structured field introducer for a data set name can be X'0008' (no data), or it can vary from X'0009' to X'0034' (9 to 52 decimal).