[ace-users] ACE/TAO: connect TAO 1.5.8 client to older TAO server.

[Douglas C. Schmidt]

Hi Michael,

   Thanks for using the PRF.

> ACE VERSION: 5.5.8
> 
> HOST MACHINE and OPERATING SYSTEM:
>         Windows XP Version 5.1 SP2, Winsock 3.10.0.103
> 
> TARGET MACHINE and OPERATING SYSTEM, if different from HOST:
>         The same target.
> 
> COMPILER NAME AND VERSION (AND PATCHLEVEL):
>         Micros. "Visual Studio 2003" 7.1.6030, SP1
> 
> THE $ACE_ROOT/ace/config.h FILE has contents:
>         >>>>>>snip
>         #define ACE_HAS_STANDARD_CPP_LIBRARY 1
>         #include "ace/config-win32.h"
>         <<<<<<snap
> 
> THE $ACE_ROOT/include/makeinclude/platform_macros.GNU FILE
>         is not existant. I use the VS project file to build ACE.
> 
> CONTENTS OF $ACE_ROOT/bin/MakeProjectCreator/config/default.features
>         is not existant. There is only one "default.rel" file.
> 
> AREA/CLASS/EXAMPLE AFFECTED:
>         My own code fails when it wants to connect to an older
>         TAO server (ca. six years old) over ethernet.

Which version of TAO are you trying to interoperate with?

> DOES THE PROBLEM AFFECT:
>     COMPILATION? No
>     LINKING? No
>     EXECUTION? Yes. Maybe ACE is affected, but shurely my application.
> 
> SYNOPSIS:
>         Connection to an old TAO server does not work. The old server
>         has a shorter IOR:xxx than the newer TAO uses as default. It
>         fails on _narrow(), which allways returns a nil object after
>         timeout of about 10 secs.
> 
> DESCRIPTION:
>         A simple CORBA client wants to call objects on a remote
>         TAO CORBA server over ethernet. This remote server is existant
>         binary-only and about six years old.
>         The client is written in C++, as is the old server. The original
>         C++ IDL file is used to generate the C++ interface files.
>         The client does:
>         * corba_init()
>         * string_to_object() with the correct IOR (is_nil() is false)
>         * _narrow()
>         The last, _narrow(), allways fails and the object is nil.
>         I debugged the session and got this call-stack:
> >>>>snip
> mymain.cpp: nbtc._narrow()
>   stu_ConfigServerIDLC.cpp: _narrow()
>     Object_t.cpp: narrow() ...if (obj->_is_a(repo_id) == false)...
> (3)   Object.cpp: _is_a() ...if (this->_stubobj()->type_id.in() != 0 &&
>                                  ACE_OS::strcmp(type_id,
>                                                 this->_stubobj()->type_id.in())
>                                  == 0) return true;
>                              return this->proxy_broker()->_is_a(this, type_id);
>         Object.cpp: proxy_broker() ...if (this->protocol_proxy_) {
> (2)                                      return this->protocol_proxy_->
>                                                 object_proxy_broker(); }
>           Remote_Object_Proxy_Broker.cpp: _is_a() ...tao_call.invoke(0, 0);
> (1)                                                  return _tao_retval.retn();
>                                                   ...
> <<<<snap
> 
> REPEAT BY: My failing example client code is:
> >>>>>snip
> try {
>     CORBA::ORB_var orb = CORBA::ORB_init(argc, argv);
>     CORBA::Object_var obj;
>     obj = orb->string_to_object(argv[1]);
>     if (CORBA::is_nil(obj.in())) {
>         return 2;
>     }
>     nbFoodServer::nbFoodServer_var refcli =
>         nbFoodServer::nbFoodServer::_narrow(obj.in());
>     if (CORBA::is_nil(refcli.in())) {
>         // here it fails and returns :-)
>         return 3;
>     }
>     refcli->activateFood(0xa8);
>     // ...
> catch(const CORBA::Exception &ex) {
>     ex._tao_print_exception("CORBA exception: ");
>     return -1;
> }
> <<<<<snap
> 
> SAMPLE FIX/WORKAROUND:
>     Not available.
> 
> Since the documentation for this ProxyBroker class is very small, I
> have no clue what exactly fails and what I could do to make client
> and server compatible.

Hopefully, someone will be able to give you some tips on how to make
things work together.  If not, I recommend you contact one of the
companies listed at

http://www.dre.vanderbilt.edu/support.html

for commercial support.

Thanks,

        Doug