Returns: An array that corresponds to the lengths of each
field in the last row fetched by
fbsql_fetch_row(), or
FALSE on error.
fbsql_fetch_lengths() stores the
lengths of each result column in the last row returned by
fbsql_fetch_row(),
fbsql_fetch_array() and
fbsql_fetch_object() in an array, starting at offset
0.
See also: fbsql_fetch_row().