warning: cannot return a local value by reference

["k_leau" <k_leau@yahoo.com>]

Hello,

I am new to Ada programming and I have the following problem:

I am using the APQ binding for working with Postgresql.

I have created the following spec "item_dbm_cls.ads" with the following:

with item_cls, apq.postgresql.client;
use item_cls, apq, apq.postgresql, apq.postgresql.client;

package item_dbm_cls is
    type item_dbm is limited private;
    function new_item_dbm(it_dbm: item_dbm) return item_dbm;

private
    type item_dbm is record
        it: item;
        connection: connection_type;
    end record;

end item_dbm_cls;

---------------------------------------
And a body "item_dbm_cls.adb" with:

package body item_dbm_cls is
    function new_item_dbm(it_dbm: item_dbm) return item_dbm is
        i_dbm: item_dbm;
    begin
        set_host_name(i_dbm.connection, host_name(it_dbm.connection));
    return i_dbm;
    end new_item_dbm;

end item_dbm_cls;

Why do I have this warning?
What mistake have I done? 

Thanks for any help.