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  1. #include <iostream>
  2. #include <cstdint>
  3. #include <utility>
  4.  
  5. template <typename T>
  6. struct noop_destructor {
  7. public:
  8. 	typedef T* pointer;
  9. 	typedef const T* const_pointer;
  10. 	typedef T& reference;
  11. 	typedef const T& const_reference;
  12.  
  13.     template<typename... Args>
  14. 	noop_destructor(Args&&... args) {
  15. 		new (reinterpret_cast<void*>(wrapped_data)) T(std::forward<Args>(args)...);
  16. 	}
  17.  
  18.     explicit noop_destructor(const noop_destructor& rhs) {
  19.     	std::copy(rhs.wrapped_data,rhs.wrapped_data+sizeof(T),wrapped_data);
  20.     }
  21.  
  22.     noop_destructor& operator=(const noop_destructor& rhs) {
  23.     	std::copy(rhs.wrapped_data,rhs.wrapped_data+sizeof(T),wrapped_data);
  24.     	return *this;
  25.     }
  26.  
  27.     pointer operator->() {
  28.     	return reinterpret_cast<pointer>(wrapped_data);
  29.     }
  30.     const_pointer operator->() const {
  31.     	return reinterpret_cast<const_pointer>(wrapped_data);
  32.     }
  33.     reference operator*() {
  34.     	return *reinterpret_cast<pointer>(wrapped_data);
  35.     }
  36.     const_reference operator*() const {
  37.     	return *reinterpret_cast<const_pointer>(wrapped_data);
  38.     }
  39. private:
  40. 	uint8_t wrapped_data[sizeof(T)] __attribute__ ((aligned (__BIGGEST_ALIGNMENT__)));
  41. };
  42.  
  43.  
  44. class A {
  45. public:
  46. 	A() : x_() {}
  47. 	A(int x) : x_(x) {}
  48. 	~A() {
  49. 		std::cout << "noop destructor call of class A" << std::endl;
  50. 	}
  51. 	void foo() {
  52. 		std::cout << "x_ = " << x_ << std::endl;
  53. 	}
  54.  
  55. private:
  56. 	int x_;
  57. };
  58.  
  59. int main() {
  60.     A a1(5);
  61.     noop_destructor<A> a2;
  62.  
  63.     a1.foo();
  64.     (*a2).foo();
  65. 	return 0;
  66. }
  67.  
Success #stdin #stdout 0s 3140KB
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stdin
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Standard input is empty
stdout
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x_ = 5
x_ = 0
noop destructor call of class A
https://ideone.com/nx3YFs
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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