Dear tree expert, As you might know, Boost.Intrusive implements an intrusive red-black tree and also a class offering red-black tree algorithms. Those algorithms were taken from the SGI STL code and optimized a bit. One of the goals of Boost.Intrusive is avoiding recursive calls to make those algorithms suitable for very big trees and/or embedded systems. The SGI STL uses two recursive algoritms: * Recursive destruction with no rebalancing * Recursive structural copy (which needs a erasing function in case a copy throws an exception). All STL implementations I'm aware of use recursive cloning and destruction. Boost.Intrusive changed the recursive tree destruction algorithm to a non-recursive one thanks to a step by step tree destruction function (unlink_leftmost_without_rebalance) that is also very useful to implement advanced tree cloning functions that might reuse old allocated nodes. However, I haven't found a non-recursive structural copy algorithm anywhere. So if you are a tree expert, I need your help to get a tree cloning function, that: * Does not use the comparison predicate or calls any function that uses it (e.g.: insert()) * Can destroy all constructed nodes in a non-recursive form if node-copying throws an exception. * It's pretty efficient ;-) Willing to help? Ion