Re: [Boost-users] [multi_index] MSVS 2005 visualizers?

Filip Konvi?ka ha escrito:

Joaquín Mª López Muñoz (28.5.2007 7:49):

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Hello Filip, I did reply this email last Thursday, I guess somehow it didn't make it to your inbox (??) I'm copying and pasting my answer here again:

Filip Konvi?ka ha escrito:

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Joaquín Mª López Muñoz (23.5.2007 18:16):

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Hello Filip,

I know nothing about VS visualizers so I'm afraid I can't help much on that part, but feel free to ask as much as you need on the internal structures of B.MI --publicly of privately if you feel this is going to be a long list of mails.

[I tried replying to your email address, but I don't know whether this ever reached you, so I retry here...]

I tried some debugging with multi_index_container > >, which is probably the simplest case. I ended up in the "space" member of "pod_value_holder", which seems to handle some alignment issues and from the name I guess it should also contain the data, but I don't see it in the debugger.

That "space" member is used as raw storage upon which the value (of type int in this case) is constructed. So, you have to reinterpret_cast to get to your value. Does the visualizer allow you to do that?

Yes, but if you look at the screenshot, you see that the space (resp. space.data_.buf) is filled with 0xcd = -51 (i.e. uninitialized) values. If I reinterpret the space member as int, I get 0xcdcdcdcd. So my conclusion is that I'm looking at the "rear" node and I need to go to the prior_ or next_ node, right?

Correct, I call it the "header" node. You must go to some other node to see actual values, right.

So I tried next_, but I got garbage again, but this time it is not 0xcdcdcdcd but something a bit different. I have inserted a "1" into the container, so I'd expect that the buffer contained [0x01 0x00 0x00 0x00].

See screenshot - the expression shown is (sorry :-)))

I'm not 100% sure, but I think you're not getting the casts right --if I'm interpreting the expression correctly, you are applying the following casts to the next_ pointer: a) to boost::multi_index::detail::sequenced_index_node_trampoline< boost::multi_index::detail::index_node_base<int> >* b) to boost::multi_index::detail::sequenced_index_node_impl* c) to boost::multi_index::detail::index_node_base<int>* Is this the sequence of casts you're meaning to apply? If so, I think this is wrong, what you should go thru is: a) to boost::multi_index::detail::sequenced_index_node_trampoline< boost::multi_index::detail::index_node_base<int> >* b) to boost::multi_index::detail::sequenced_index_node< boost::multi_index::detail::index_node_base<int> >* c) to boost::multi_index::detail::index_node_base<int>* That is, if x is of type sequenced_index_node_impl you get to the full node by evaluating: (boost::multi_index::detail::index_node_base<int>*) (boost::multi_index::detail::sequenced_index_node< boost::multi_index::detail::index_node_base<int> >*) (boost::multi_index::detail::sequenced_index_node_trampoline< boost::multi_index::detail::index_node_base<int> >*)x HTH, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo