[omniORB] C++ mapping of IDL struct

[Sean Parker]

Thanks a ton - I'll try it
 
   Cheers and God Bless
     Sean



--- Carlos <carlos at canama.net> wrote:

> El mar, 17-04-2007 a las 07:18 -0700, Sean Parker
> escribió:
> > 
> > Hello -
> > 
> >   I have a question about the "proper" way to return
> > structs from server methods. (I end up with a memory
> leak,
> > but the data gets through fine)
> > 
> > For example:
> > 
> >   <IDL code>
> >   struct MyStruct
> >   {
> >       long a;
> >       string b;
> >   };
> >   interface X
> >   {
> >       MyStruct doit();
> >   }
> >   <end IDL code>
> > 
> > Then in C++:
> > 
> >   <C++ code>
> > 
> >   MyStruct*
> >   X_impl::doit()
> >   {
> >       MyStruct* ms = new MyStruct();
> >       ms->a = 0;
> >       ms->b = ::CORBA::string_dup( "hello" );
> >       return ms;
> >   }
> > 
> >   <end C++ Code>
> > 
> > 
> 
> I think this code is correct, but perhaps the memory leak
> is in client
> side, in order to manage the return in a correct way:
> 
> X_var x_var = ....
> 
> MyStruct_var s_var = x_var->doit();
> 
> Now the return pointer is owned by s_var, so when s_var
> gets out of
> scope the destructor properly frees the memory.
> 
> And in server side perhaps a better implementation is:
> 
> MyStruct*
> X_impl::doit()
> {
> 	MyStruct_var s_var = new MyStruct();
> 	s_var->a = 0;
> 	s_var->b = ::CORBA::string_dup("Hello");
> 	return s_var._retn();
> }
> 
> This implementation is better because if inside the
> method a exception
> is raised the destructor of MyStruct_var is called, so
> you don't get a
> memory leak.
> 
> Cheers.
> 
> Carlos.
> 
> > I suppose there are "preferred" ways to do this, so
> that's
> > what I'm asking, what's the preferred (or only) way to
> do
> > this w/o memory leaks? When using valgrind, I always
> have a
> > leak of both the string 'b' and the MyStruct
> allocation. Is
> > there a alloc_buf function I need to use, as in
> creating
> > sequences of structs? (I thought of always returning
> > sequences of size one, since I do sequences alot
> elsewhere
> > w/o leaks, but that seems klugy...)
> > 
> >   Any help appreciated - 
> >     Thanks and God Bless
> > 
> >       Sean  
> > 
> > P.S. I'm using oo 4;
> > 
> > P.P.S. the C++ mapping doc from OMG suggestes something
> > like a _rtrn() function, as an example for
> implementations
> > to do things, but not sure that omniORB has such a
> thing...
> > 
> > 
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam?  Yahoo! Mail has the best spam
> protection around 
> > http://mail.yahoo.com 
> > 
> > _______________________________________________
> > omniORB-list mailing list
> > omniORB-list at omniorb-support.com
> >
>
http://www.omniorb-support.com/mailman/listinfo/omniorb-list
> > 
> > 
> 
> 





God Bless 
    Sean Parker 




__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com