With a traditional "hand-rolled" doubly-linked list, if you have a

reference to a Node, you can traverse from that node to the end of the

list easily. Just check for "pNext == NULL" to know when you're at the

end. You don't need any reference to the owning "list container"

object.

However, I can't seem to accomplish the same with boost::intrusive::list.

Traversal with an intrusive::list's iterator is done STL-style, and

for that you need to compare to the container's ".end()" value.

I am aware of the "s_iterator_to" function[1], which can statically

get an iterator from a node, but there doesn't seem to be any way to

statically get a usable ".end()" value to compare to. There is also

"container_from_end_iterator"[2], which gives the container if you

have "end()" available already — not quite what I want, but I guess

shows that end() is intimately tied to the container.

I also notice that if I have an iterator to the last element in a

list, and I increment it (++iterator), no error is given. But if I try

to dereference it, I get garbage data.

Peeking into the implementation, from what I can tell,

boost::intrusive::list is actually a circular list, with a special

"root node" that the container owns, and which represents the "end".

So, iterating beyond the end gives you that root node.

I guess my questions are:

(1) Is my analysis above correct? I feel I might have missed something

wading through all the templates, and the docs I've found don't

discuss these implementation details.

(2) Is there any way to accomplish what I want? That is: iterating

from an arbitrary node to the end of the list, *without* a reference

to the owning container?

(3) [aside] If the answer to the above is "no", does anyone know what

the rationale is for this design choice? It seems odd that such a

basic feature of a traditional hand-made intrusive list would be

dropped if there were no benefit.

Thanks

-John

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