Checking if an iterator is valid

Question

Is there any way to check if an iterator (whether it is from a vector, a list, a deque...) is (still) dereferenceable, i.e. has not been invalidated?

I have been using try-catch, but is there a more direct way to do this?

Example: (which doesn't work)

list<int> l; for (i = 1; i<10; i++) {     l.push_back(i * 10); }  itd = l.begin(); itd++; if (something) {     l.erase(itd); }  /* now, in other place.. check if it points to somewhere meaningful */ if (itd != l.end()) {     //  blablabla } 

Answer 1

I assume you mean "is an iterator valid," that it hasn't been invalidated due to changes to the container (e.g., inserting/erasing to/from a vector). In that case, no, you cannot determine if an iterator is (safely) dereferencable.