Markus Schöpflin escribió:
Hello,
in the file mem_algo_common.hpp there is a class basic_multiallocation_iterator (line 50ff).
This class contains both definitions for operator* and operator->, where operator* is implemented as:
value_type operator*() const { value_type v = (char*)detail::get_pointer(next_alloc_.next_); return v; }
and operator->() as:
pointer operator->() const { return &operator*(); }
The second definition confuses both me and my compiler. Does &operator*() actually mean &(*this)? If yes, wouldn't this mean that operator-> returns the address of a stack allocated result variable, namely the address of the result of operator*? If no, what does this actually mean?
You are right. I'm returning the address of a temporary! I think conceptually the iterator is wrong. I should return char & for operator*() instead of char *. char *should be returned by operator->. However this makes the code uglier: multiallocation_iterator it = ... for(...) //placement new new(&*it++) T(); instead of for(...) //placement new new(*it++) T(); If I want basic_multiallocation_iterator to be a well-formed iterator I need to define operator->() so I think I'll need to change the interface of this class (I doubt anyone is using it). Give me some time to change it and pass the tests again. Regards, Ion