[Bug libstdc++/56437] basic_string assumes that allocators are default-constructible

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56437



--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-02-25 
00:11:16 UTC ---

C++11 allocators are not required to define any of these:



   typedef T* pointer;

   typedef const T* const_pointer;

   typedef T& reference;

   typedef const T& const_reference;

   typedef unsigned size_type;

   typedef int difference_type;

   template <class U> struct rebind { typedef MyAllocator<U> other; };



But if your allocator fails to define any of them then std::string (and some of

the other containers) will fail to compile. This is a known issue.