Process complex qualifications

In the following figure, the am_getnext purpose function attempts to disqualify source records. It creates rows for fully qualified source records and for those that it cannot disqualify.

Figure 1. Sample am_getnext purpose function

mi_integer sample_getnext(sd,retrow,retrowid)
   MI_AM_SCAN_DESC   *sd;
   MI_ROW                    **retrow
   MI_AM_ROWID_DESC  *retrowid;    /* Store rowid. */
{
   my_data_t    *my_data;
   MI_ROW_DESC            *rd;
   MI_AM_TABLE_DESC *td;
   MI_AM_QUAL_DESC  *qd;
   td = mi_scan_table(sd); /* Get table descriptor. */
   rd = mi_tab_rowdesc(td); /* Get key column data types. */
   my_data = (my_data_t *)mi_tab_userdata(td); /* Get pointer to user
data.*/
   /* Evaluate keys until one qualifies for return to caller.. */
   for (;;)
   {
      if ( ! my_data ) return MI_NO_MORE_RESULTS;
      if ( eval_qual(sd, qd, my_data)== MI_TRUE)
      {
         mi_id_setrowid(retrowid, current->rowid);
         mi_id_setfragid(retrowid, current->fragid);
         return MI_ROWS;
      }

      my_data->rowpr++;
   } /*End loop.*/
}/* End getnext.*/