The length part of a variable-length field represents the current length of the field measured in characters. For character fields, this length also represents the current length in bytes. For double-byte fields (graphic and UCS-2), this represents the length of the field in double bytes. For example, a UCS-2 field with a current length of 3 is 3 double-byte characters long, and 6 bytes long.
The following sections describe how to best use variable-length fields and how the current length changes when using different operation codes.