c++ - May STL iterator methods throw an exception

Question

Destructors may not throw exceptions (so stack unwinding can complete during exception handling), and must deallocate any resources allocated to the object (so no resources leak). A design for an object that contains several other objects (or is allocated several resources) might record pointers to them in an STL container. The destructor would therefore use the following iterator-related methods:

• begin(), end() for the container
• operator++ for a valid iterator
• operator* or operator-> for a valid iterator

But to guarantee that the destructor both does not throw exceptions and deallocates its resources you would need to rely on those methods never throwing exceptions.

Is it safe to rely on those methods never throwing exceptions? It is hard to imagine a practical implementation that would throw exceptions, as under the hood an STL iterator is essentially a pointer. But does standard C++ require that those methods never throw exceptions? I've not found a clear statement in the C++ standard.

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Edit: The interesting case is for C++ 03 when you want to have a container of pointers to resources. There are good reasons for doing this; for example, if you have polymorphic resources. As Bj?rn Pollex points out in his answer, if you use a container of resources (such as a std::list< Resource >) rather than a container of pointers to resources, the destructor of the container will take care of destruction (deallocation) of the Resource objects for you.

Answer 1

operator++ for a valid iterator

The C++ standard (I refer to N3290 draft) does not give nothrow guarantee for increment operator of iterators.

For example, std::istreambuf_iterator::operator++ effects in call to std::basic_streambuf::sbumpc. The sbumpc may call uflow which in turn may throw exception.