自定义 unique_ptr delete

  1. template<typename _Tp>
  2.     struct default_delete
  3.     {
  4.       /// Default constructor
  5.       constexpr default_delete() noexcept = default;
  7.       /** @brief Converting constructor.
  8.        *
  9.        * Allows conversion from a deleter for objects of another type, `_Up`,
  10.        * only if `_Up*` is convertible to `_Tp*`.
  11.        */
  12.       template<typename _Up,
  13.            typename = _Require<is_convertible<_Up*, _Tp*>>>
  14.     _GLIBCXX23_CONSTEXPR
  15.         default_delete(const default_delete<_Up>&) noexcept { }
  17.       /// Calls `delete __ptr`
  18.       _GLIBCXX23_CONSTEXPR
  19.       void
  20.       operator()(_Tp* __ptr) const
  21.       {
  22.     static_assert(!is_void<_Tp>::value,
  23.               "can't delete pointer to incomplete type");
  24.     static_assert(sizeof(_Tp)>0,
  25.               "can't delete pointer to incomplete type");
  26.     delete __ptr;
  27.       }
  28.     };