Erase element from std::list, old iterators still valid?

[Chris_F]

Lest say I have a std::list of items, and some of these items are being tracked by an iterator held someplace else. If I remove an element from the list, are these iterators still valid?

[nuzzle]

Yes for std::list they are. If you insert or delete an element iterators to other elements are still valid. See The C++ Standard Library, a Tutorial and Reference by Josuttis (p. 167).

Still, I generally play it safe and assume all iterators get invalidated whenever a container is restructured.

[Zachm]

See here:

"Lists have the important property that insertion and splicing do not invalidate iterators to list elements, and that even removal invalidates only the iterators that point to the elements that are removed.

The ordering of iterators may be changed (that is, list<T>::iterator might have a different predecessor or successor after a list operation than it did before), but the iterators themselves will not be invalidated or made to point to different elements unless that invalidation or mutation is explicit."

Regards,
Zachm

[Chris_F]

Thanks, Zachm.

I'm afraid I have to rely on that property of std::list, so I can't play it safe.

[nuzzle]

Thanks, Zachm.

Was there something wrong with my reply?

I'm afraid I have to rely on that property of std::list, so I can't play it safe.

Restructuring while processing is the programming equivalent of sawing off the branch one is sitting on. There's almost always a better option available.