(PHP 4, PHP 5 < 5.2.1)
ifx_fieldtypes — List of Informix SQL fields
$result_id
   ) : array
   Returns an associative array with fieldnames as key and the SQL
   fieldtypes as data for the query associated with
   result_id.
  
result_id
       result_id is a valid resultid returned by
       ifx_query() or
       ifx_prepare() (select type queries only!).
      
   Returns an associative array with fieldnames as key and the SQL
   fieldtypes as data for query with
   result_id.  Returns FALSE on error.
  
Example #1 Fieldnames and SQL fieldtypes
<?php
$types = ifx_fieldtypes($resultid);
if (is_array($types)) {
    foreach ($types as $fname => $val) {
        echo "$fname:\t type = $val\n";
    }
}
?>