Boost C++ Libraries

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Struct template has_pointer_plus_2_bits<void *, N>

boost::intrusive::has_pointer_plus_2_bits<void *,N>

template<std::size_t N> 
struct has_pointer_plus_2_bits<void *, N> {
  static const bool value;
};

This is an specialization for raw pointers. Raw pointers can embed two extra bits in the lower bits if the alignment is multiple of 4.