The tmlen routine determines the display length of the data type.

This routine returns the default and worst-case lengths for a data type if it were to be printed as text, for example, by a terminal monitor. Although user-defined data types are not returned to a terminal monitor as the user-defined types, this routine is needed by various trace flags and error formatting within the DBMS Server.

Place the address of this routine in the dtd_tmlen_addr field of the IIADD_DT_DFN structure.