There is no current way to determine the duplication factor (also known as the multiplicity) using the conditional assembly language. This is a known requirement for which the suggested solution is a new SYSATTRD function (for "duplication factor"), which would probably return the factor if already defined or 1 by default, but we haven't yet got round to it.
The duplication factor is however available in the ADATA DC/DS record, which is probably the best method of obtaining that information for an existing data structure. Jonathan Scott, HLASM IBM Hursley, UK
