Ovanes Markarian
Hello Joaquín,
Hi Ovanes,
the doc states in erase that an iterator or end-iterator is returned when erasing an element. What was the rationale behind returning the iterator? Where other members return the number of elements being removed.
To be in accordance with the standard. As others have pointed out, prior versions of the standard incorrectly dictated that for some containers erase(iterator) return void, but this was later fixed, see http://www.boost.org/libs/multi_index/doc/release_notes.html#boost_1_33_1 for details.
My point is that end-iterator is also returned when erasing an element where iterator points one before the end iterator. Now to be sure that the specified element was really removed my call must either use the key and search for that element again or compare the size before and after the erase call.
erase(iterator) never fails if used legally: providing it with an iterator from another container, which is illegal, results in undefined behavior. Enabling the safe mode as Andrew suggests can help you *debug* your problem, but shouldn't be used as a library feature in production code --safe mode incurs a considerable runtime penalty. If you really need to call erase(iterator) with iterators from another container, the solution would be to refactor your code so as to store pair(iterator,container&)s rather than iterators and do the check before actually executing erase(). Joaquín M López Muñoz Telefónica Digital