Re: [boost] shared_ptr question

From: H (h.v.niekerk_at_[hidden])
Date: 2005-06-22 07:13:52

Rob Stewart wrote:
> From: H <h.v.niekerk_at_[hidden]>
> 
>>Martin Bonner wrote:
>>
>>>From: H. van Niekerk [mailto:h.v.niekerk_at_[hidden]]
>>>
>>>Incidentally, I don't think the presence of three .cpp files is directly
>>>relevent.  I suspect that the relevent factor is that you have three
>>>*functions*, and your problem is passing the data between them.
>>>
>>
>>Thank you for your response. I hope the code below explains more:
>>
>>Master.cpp
>>{
>>	Client c;
>>	c.readFromSatellite(input);
>>	cout << "input = " << input << endl;
>>}
>>
>>Client.cpp
>>{
>>	Satellite s;
>>
>>	readFromSatellite(input)
>>	{
>>		s.readFromInterface(input);
>>		return input;
>>	}
>>}
>>
>>Satellite.cpp
>>{
>>	readFromInterface(input)
>>	{
>>		// Here the actual reading is done
>>		fti->writeAndReadAllData(output, input);
>>		return input;
>>	}
>>}
> 
> 
> As Martin said, the separate files aren't relevant.  Also, the
> usage and declarations of your functions aren't consistent.
> 
> Let's see if I can recast your problem to something a little
> simpler to discuss:
> 
>    void function2(some_type data) // stores stuff in caller's object
>    {
>       read_something_from_somewhere(data);
>    }
> 
>    void function1(some_type data) // stores stuff in caller's object
>    {
>       function2(data);
>    }
> 
>    void function3(some_type data)
>    {
>       // do something useful with data
>    }
> 
>    int main()
>    {
>       some_type data; // some pointer type
>       function1(data); // stores stuff in data
>       function3(data);
>    }
> 
> Is that a good approximation of what you want?
> 
> If so, some_type should be boost::shared_ptr<something> and the
> rest should just work.  Of course, you can avoid using
> boost::shared_ptr if function1() and function2() take non-const
> references to some_type:
> 
>    void function2(some_type & data) // stores stuff in caller's object
>    {
>       read_something_from_somewhere(data);
>    }
> 
>    void function1(some_type & data) // stores stuff in caller's object
>    {
>       function2(data);
>    }
> 
>    void function3(some_type const & data)
>    {
>       // do something useful with data
>    }
> 
>    int main()
>    {
>       some_type data; // not a pointer type
>       function1(data); // stores stuff in data
>       function3(data);
>    }
> 
After reviewing the groups on this news-server, I think I'm posting to 
the wrong group. If you agree with that view, please let me know. I'll 
follow up to the user group then.

H.