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Subject: Re: [boost] [interprocess] preparing containers
From: vicente.botet (vicente.botet_at_[hidden])
Date: 2008-12-03 04:29:02

----- Original Message -----
From: "Thorsten Ottosen" <thorsten.ottosen_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Wednesday, December 03, 2008 10:17 AM
Subject: Re: [boost] [interprocess] preparing containers

> Ion Gaztañaga skrev:
>> Thorsten Ottosen wrote:
> [snip]
>>> In particular, if I want to use boost::ptr_vector, then do I need to
>>> have stateful allocators (both the normal container allocator, and the
>>> clone_allocator)?
>> Sorry, I'm not familiar with ptr_containers. If you can give me some
>> hints on what's clone_allocator for, I'll be glad to help you to make
>> ptr_container compatible with shared memory allocators. Just one issue:
>> shared memory does not support virtual functions, so I don't think
>> polymorphic cloning will be usable at all.
> Currently the clone-allocators are a stateless customization point for
> cloning. It tells the containers how to clone the (indirectly) held
> pointees.
> I guess support for virtual functions is needed, except for the most
> trivial cases. So what does it mean exactly, that shared memory does not
> support virtual functions? Can I never call a virtual function on an
> object if that object's memory is shared? (In which case I'm a bit
> puzzled :-))

The address of the virtual table depends on the process, so can not be shared. As consequence we can not have virtual function on objects stored on shared memory.


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