Are pointers allowed as keys in ordered STL containers?

Question

There\'s this other question asking about how comparing pointers is supposed to be interpreted wrt the C++ Std.

So I was wondering what the C++ Std has to say about

Answer 1

Yes. Pointers are comparable via operator<().

If the pointers do not point to the elements of the same array or elements within the same object the c++ standard says the behavior is unspecified [expr.rel].

The standard says unspecified behavior means it's implementation defined [defns.unspecified].

If your compiler guaranties a strict weak order of pointers you can use any pointer with associative containers.

Most compilers do pointer comparison by comparing the memory addresses. On most architectures this comparison forms a strict weak order.

Therefore it's safe to use pointers as keys.