David Abrahams wrote:
on Tue Dec 11 2007, Joaquín Mª López Muñoz <joaquin-AT-tid.es> wrote:
David Abrahams ha escrito:
on Sun Dec 09 2007, Ion Gaztañaga <igaztanaga-AT-gmail.com> wrote:
23.1.3.1 Exception safety guarantees [unord.req.except]
1 For unordered associative containers, no clear() function throws an exception. No erase() function throws an exception unless that exception is thrown by the container’s Hash or Pred object (if any).
Why this difference? I hope someone knows the answer ;-) Because unordered associative containers may rehash when erasing. I think unordered containers are *not* allowed to rehash when erasing: see N2461, 23.1.3/8
"...Rehashing invalidates iterators, changes ordering between elements,..."
and 23.1.3/12
"...The erase members shall invalidate only iterators and references to the erased elements."
so the conclusion is that erase can't rehash
Sorry, how do you reach that conclusion? It says that erase can invalidate iterators, and the only thing it says that rehashing invalidates is iterators.
If I'm understanding correctly, erase can only invalidate iterators (to the erased elements*, but rehashing invalidates iterators to all elements. Therefor, erase cannot rehash. Did I get that right? -- Eric Niebler Boost Consulting www.boost-consulting.com