Re: [boost] shared_ptr question

22 Jun 2005

      ...
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?
Yes, that looks like it.
...
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);
   }
OK. The original way was:

auto_ptr<FtInterface> fti (ftGetIfFromFactory(device, connection));

With shared_ptr would it become like this:

void function2(boost::shared_ptr fti (ftGetIfFromFactory(device, 	 
connection))
{
	...
	fti->writeAndReadAllData(out,inp);
}

void function1(boost::shared_ptr fti (ftGetIfFromFactory(device, 	 
connection))
{
	function2(data);
}

int main()
{
	boost::shared_ptr<FtInterface> fti (ftGetIfFromFactory(device, 	 
connection));
	function1(fti (ftGetIfFromFactory(device, 		connection));
}

What would be the benefit of using non-const references?

Thank you for helping.

Huub