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

From: Wu Yinghui, Freddie (yhwu_at_[hidden])
Date: 2006-10-19 22:48:52

> And thus spake "Baranowski, Daniel" <dbaranowski_at_[hidden]>
> Thu, 19 Oct 2006 14:25:46 -0400:
> 
>> You'll see that the objects are or are not getting destroyed (they are
>> on my comp). I played around with this in VC 8 and the memory usage
>> didn't go up like yours. Here's how it looks on my system:
> 
> Well, I have to apologise in one respect, the memory definitely gets
> re-used, which is a relief. What remains is the impossibly-large memory
> footprint of >10kb per object, which I have to investigate further. At the
> moment it is such that a list of a little over 5000 (small) POD objects
> eats well over 100MB of memory, and that just can't be right... however I
> will check if this is really caused by the shared_ptr...
> 
> Anyway, thank you all for your suggestions and your time. You have been a
> great help.
> 
> Regards,
> Robert

Hi,

As what Andrew has already mentioned, using shared_ptr for simple POD is
way too heavy in terms of memory overhead.

I'd suggest you try two alternatives and see which one fits you more:

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.

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.

Hope this helps...

Cheers,

Freddie

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Wu Yinghui, Freddie
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