Gnatcom problem with MS XML

Gnatcom problem with MS XML

[bubble]

dear all:
I am learning how to use Gnatcom .
I do a COM's practice ; the practice is Microsoft XML COM Library(msxml3.dll 
and msxml5.dll) .

I get some problem in practice and I can not sure where problem is?
I write my questions in code comment.
if you can understand my problem , could you explain why?
thank you.

my OS is windows XP.
my compiler is GNAT 3.15P +  Gnatcom


--------------------------------------------------------------------------------------------
-------this is full complete test code.
----------------------------------------------------------------------------------------------

with Gnatcom;
with Gnatcom.Initialize;
with Gnatcom.Bstr;
with Gnatcom.Variant;
with Gnatcom.Types;
with Ada.Text_Io;

with Msxml5.Ixmldomdocument_Interface;
with Msxml5.Ixmldomelement_Interface;
with Msxml5.Ixmldomnode_Interface;


procedure Test is
   use Msxml5;
   use Gnatcom;
   Dom : Ixmldomdocument_Interface.Ixmldomdocument_Type;

   P_Root : Pointer_To_Ixmldomelement;
   Node   : Ixmldomelement_Interface.Ixmldomelement_Type;

 Node2   : Ixmldomelement_Interface.Ixmldomelement_Type;

begin
   Gnatcom.Initialize.Initialize_Com;                                        
                           --- initialize COM environment
   Ixmldomdocument_Interface.Create(Dom,Clsid_Domdocument);
   P_Root 
:=Ixmldomdocument_Interface.Createelement(Dom,Gnatcom.Bstr.To_Bstr("root"));
   Ixmldomdocument_Interface.Putref_Documentelement(Dom,P_Root );
   Ixmldomelement_Interface.Attach (Node,P_Root );
   Ixmldomelement_Interface.Attach (Node2,P_Root ); ---here I get problem

-----------------------
------------------------- why can not attach P_Root to Node twice?
-------------------------
--------------------------    if I write the statement " 
Ixmldomelement_Interface.Attach (Node,P_Root ); "  twice.
--------------------------    such as
--------------------------
-------------------------    Ixmldomelement_Interface.Attach (Node,P_Root ); 
<-  pass
--------------------------   Ixmldomelement_Interface.Attach (Node,P_Root ); 
<- crash here
--------------------------
--------------------------   it will crash at second statement.
--------------------------
--------------------------   if my code is
--------------------------
-------------------------   Ixmldomelement_Interface.Attach (Node,P_Root ); 
<- pass
-------------------------   Ixmldomelement_Interface.Attach (Node2,P_Root ); 
<- pass
--------------------------
-------------------------- perfect work and I still don't know why?
--------------------------

   for I  in 1 .. 2 loop
      declare
         Tag       : Types.Bstr                             := Bstr.To_Bstr 
("child");
         Ns        : Types.Bstr                             := Bstr.To_Bstr 
("");
         Node_Type : Types.Variant                          := 
Variant.To_Variant (Node_Element);
         P_Child   : Pointer_To_Ixmldomnode;
         Child     : Ixmldomnode_Interface.Ixmldomnode_Type;
      begin
         P_Child:=Ixmldomdocument_Interface.Createnode (Dom, Node_Type, Tag, 
Ns);
         declare
            X_Child : Pointer_To_Ixmldomnode := 
Ixmldomelement_Interface.Appendchild (Node, P_Child);
         begin
            ---------
            ---------
            ---------  here I do attach x_child to child over twice again
            ---------  the code is
            ---------
            ---------- Ixmldomnode_Interface.Attach (Child,X_Child );   <- 
pass
            ---------- Ixmldomnode_Interface.Attach (Child,X_Child ); 
<-pass
            ---------
            ---------
            Ixmldomnode_Interface.Attach (Child,X_Child );
            Ixmldomnode_Interface.Attach (Child,X_Child );
         end;
         Bstr.Free(Tag);
         Bstr.Free(Ns);
      end;
   end loop;


   declare
      Xml : Gnatcom.Types.Bstr;
   begin
      Xml:=Ixmldomdocument_Interface.Get_Xml(Dom);
      Ada.Text_Io.Put_Line(Gnatcom.Bstr.To_Ada(Xml));
      Gnatcom.Bstr.Free(Xml);
   end;



end;

Re: Gnatcom problem with MS XML

[Stephen Leake]

"bubble" <bubble@riskm.com.tw> writes:

> I am learning how to use Gnatcom .

I can't help you, but a better place to ask for help on Gnatcom is the
Gnavi mailing list; gnavi-discuss@lists.sourceforge.net. See
http://lists.sourceforge.net/lists/listinfo/gnavi-discuss.


-- 
-- Stephe

Re: Gnatcom problem with MS XML

[David Botton]

On 2005-03-18 05:58:57 -0500, "bubble" <bubble@riskm.com.tw> said:

> -----------------------
> ------------------------- why can not attach P_Root to Node twice?

Because you should in general use Query not Attach for all assignments 
accept when Attaching a raw pointer. See the comments on the specs for 
Query and Attach.