{ \
  template<> \
  class vector<__VA_ARGS__, std::allocator<__VA_ARGS__> >  \
    : public vector<__VA_ARGS__, EIGEN_ALIGNED_ALLOCATOR<__VA_ARGS__> > \
  { \
    typedef vector<__VA_ARGS__, EIGEN_ALIGNED_ALLOCATOR<__VA_ARGS__> > vector_base; \
  public: \
    typedef __VA_ARGS__ value_type; \
    typedef vector_base::allocator_type allocator_type; \
    typedef vector_base::size_type size_type;  \
    typedef vector_base::iterator iterator;  \
    explicit vector(const allocator_type& a = allocator_type()) : vector_base(a) {}  \
    template<typename InputIterator> \
    vector(InputIterator first, InputIterator last, const allocator_type& a = allocator_type()) : vector_base(first, last, a) {} \
    vector(const vector& c) : vector_base(c) {}  \
    explicit vector(size_type num, const value_type& val = value_type()) : vector_base(num, val) {} \
    vector(iterator start, iterator end) : vector_base(start, end) {}  \
    vector& operator=(const vector& x) {  \
      vector_base::operator=(x);  \
      return *this;  \
    } \
  }; \
}
This section contains a convenience MACRO which allows an easy specialization of std::vector such that for data types with alignment issues the correct allocator is used automatically.