Re: [Boost-users] Memory problem using shared_ptr w/ STL-containers, gcc

From: Robert Fendt (robert_at_[hidden])
Date: 2006-10-20 02:40:39

And thus spake "Wu Yinghui, Freddie" <yhwu_at_[hidden]>
Fri, 20 Oct 2006 10:48:52 +0800:

> 1) Store the POD directly in your container. AFAIK, copying 2 integers
> in and out of the container is not heavy at all in most cases. So that
> might help remove the trouble of using shared_ptr all together.

Well, my example was boiled-down. In fact, so very much boiled down that
it did not allow me to see that my problem was in fact connected to my
actual structure, which is a POD container a bit larger than 2 integers.
Furthermore it is used a lot at different places, so copying a pointer is
definitely cheaper-- even if it is a shared_ptr.

The actual problem was PEBKAC: a supposed-to-be-static member (a
stringstream), that was there for data conversion purposes and because it
made more sense than making it global, was not after all static and got
re-created thousands of times. So my POD container was not, after all,
POD. Actually, I am a bit embarassed about this... lesson learned: never
ever code at 3:00 in the morning, and if you do it anyway, look for
problems in your own code rather than blaming some library...

> 2) If you insist on storing pointer to the POD in the container, why not
> take a look at Boost.Pointer_Container library? The library provides the
> whole range of containers for pointer types. Better still, memory
> management on destruction is automatic in the pointer containers.

Thanks for the suggestion, this sounds very interesting. I will definitely
look into it.

Regards,
Robert