ESQL/C vs. SQLDA

Hi, I've got an ESQL/C application (Solaris, Informix SE v7.2). There are cases where I need to rebuild the SELECT statments with the same fields list but a different query. In an effort to wring out a bit more performance, I decided that I could avoid the DESCRIBE overhead and reuse the fields clause SQLDA since the fields list never changed. This worked well until I discovered that Informix creates an SQLDA that contains pointers (i.e. sqlname) to data outside the SQLDA structure allocated by Informix. Did I miss something? If so, would someone to point me at the documentation that says I am required to do a DESCRIBE after 'every' PREPARE? Thanks Steven.