[omniORB] Resizing a string sequence

[Gary Duzan]

In Message <200311242331.44727.jcronje at dsp.sun.ac.za> ,
   Johan Cronje <jcronje at dsp.sun.ac.za> wrote:

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=>On Monday 24 November 2003 22:55, Gary Duzan wrote:
=>> In Message <200311241740.21950.jcronje at dsp.sun.ac.za> ,
=>>    Johan Cronje <jcronje at dsp.sun.ac.za> wrote:
=>>
=>> =>protected:
=>> =>  attribute_list component_attr;
=>> =>// this is a global variable, as it is returned by following function
=>> =>
=>> =>  attribute_list* return_attributes()
=>> =>  {
=>> =>     ...
=>> =>     component_attr.length(number_of_attributes);
=>> =>     for (int i = 0; i < number_of_attributes; i++){
=>> =>        component_attr[i] = CORBA::string_dup(string_obtained_from_fn);
=>> =>     }
=>> =>     ...
=>> =>  }
=>>
=>>    Are you returning &this->component_attr here? You can't do that.
=>> Since "the caller owns the memory", the ORB will try to delete your
=>> sequence object and fail, potentially causing all sorts of nastiness
=>> similar to what you are seeing. You'll have to allocate and return a
=>> new sequence object each time.
=>
=>Yep, I returned the global component_attr. I am gonna try the following,
=>if you guess it will work, you don't need to reply, as (assuming it works)
=>I'll have the answer.
=>
=>  attribute_list *component_attr;
=>
=>Then in the fn:
=>  attribute_list* return_attributes()
=>  {
=>    ...
=>    delete component_attr; // remove old value
=>    component_attr = new attribute_list;
=>    for (....)
=>      (*component_attr)[i] = ...
=>    ...
=>    return component_attr;
=>  }
=>
=>If there is something horribly wrong with this approach, _please_ let me know!

   Only that you are keeping an invalid pointer to the sequence around
for no reason. If you really want to have a copy of the sequence, go
ahead and make it a member, populate it, and:

	return new attribute_list(component_attr);

or something like that. Otherwise, just make component_attr a local.

					Gary Duzan
					BBN Technologies
					A Verizon Company