OCI error 1002

I'm developing an application with Oracle 7.3.2.1.0 on Digital Unix 3.2 using non-blocking mode. I am encountering situations where in my ofen loop I am getting ORA-01002: fetch out of sequence. In the previous iteration the cda.rc value is 0 not 1403. I have determined that when this happens, the previous ofen actually fetched the last set of rows.

Here's the a sample of my code:
void OCIDB::fetch_rows(sword ncols, ostrstream *res_ostr) {

    ub4 n_rows = 0;

    for (;;) {

        /* Fetch a row.  Break on end of fetch,
           disregard null fetch "error". */
        do {
             int retval = ofen(&cda, nrows_fetch);
             cout << "ofen returned " << retval << ", cda.rc = " << cda.rc
                  << endl;


        } while (cda.rc == BLOCKED);



        if (cda.rc != SUCCESS) {
            if (cda.rc != NULL_VALUE_RETURNED && cda.rc != NO_DATA_FOUND) {
                oci_error();
                logFatal << "OCI Error after " << n_rows << ": "
                         << strerror(errno) << endm;
                exit(1);
            }

            if ((cda.wrn & 0x1) && (cda.wrn & 0x2)) {
                cout << "***** ERROR ****** data truncated" << endl;
            }


        }


        // the rpc is cumulative, so we need to calculate how many returned
        // in this fetch.
        ub4 nr = cda.rpc - n_rows;
        n_rows = cda.rpc;

        cout << "got " << nr << " in this fetch (wanted " << nrows_fetch
             << ")" << endl;
        
        for (int row = 0; row < nr; row++) {
            // process each row returned, not important for this sample.


        }


        if (cda.rc == NO_DATA_FOUND) {
            break;


        }

--
===============================================================================
Ian Hogg						ianhogg_at_cs.umn.edu
                                                        (612) 424-6332