Some components might produce a very large number of CTEs, and because the CTRF exit routine might be called for each one, consider exploiting the 4-kilobyte work area, or the CTXIUSER and CTXIUSRL fields to anchor storage obtained by the exit routine. On the first call, IPCS initializes CTXIUSER and CTXIUSRL to a value of zero. If, on some subsequent call (call n), the exit routine updates either of these fields, the updated information appears in the field as input to the exit routine on the next call (call n+1). CTRACE frees any storage anchored in CTXIUSER.