nullptr.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_NULLPTR_HH
#define DUNE_NULLPTR_HH
 
#if ! HAVE_NULLPTR
 
const                        // this is a const object...
class dune_nullptr_t {            // of type nullptr_t
public:
  template<class T>          // convertible to any type
  operator T*() const        // of null non-member
  { return 0; }              // pointer...
  template<class C, class T> // or any type of null
  operator T C::*() const    // member pointer...
  { return 0; }
private:
  void operator&() const;    // whose address can't be taken
} nullptr = {};              // and whose name is nullptr
 
namespace Dune {
  typedef dune_nullptr_t nullptr_t;
}
 
template<class T>
bool operator == (T* t, dune_nullptr_t)
{
  return (t == static_cast<T*>(nullptr));
}
 
template<class T>
bool operator == (dune_nullptr_t, T* t)
{
  return (t == static_cast<T*>(nullptr));
}
 
#else
 
#include <cstddef>
 
namespace Dune {
  using std::nullptr_t;
}
 
#endif // HAVE_NULLPTR
 
#endif // DUNE_NULLPTR_HH