[C++] destroy/destroy_at/destroy_n

개요

• destroy
  • 범위의 객체를 파괴
• destroy_at
  • 객체를 파괴
• destroy_n
  • 범위의 시작부터 n개의 객체를 파괴

예제

• 코드

   #include <iostream>
   #include <memory>
      
   using namespace std;
      
   class Test {
   	private:
   		// int i;
      
   	public:
   		int i;
      
   		Test(int i) : i(i) {}
   		~Test() { cout << "~Test() : " << this->i << endl; }
   };
      
   void destroy_test() {
   	cout << __func__ << " start" << endl;
      
   	constexpr int size = 3;
      
   	unsigned char pool[sizeof(Test) * size];
      
   	for (int i = 0; i < size; ++i) {
   		new (pool + (sizeof(Test) * i)) Test(i);
   	}
      
   	auto ptr = launder(reinterpret_cast<Test *>(pool));
      
   	destroy(ptr, ptr + size);
      
   	cout << __func__ << " end" << endl;
   }
      
   void destroy_at_test() {
   	cout << __func__ << " start" << endl;
      
   	constexpr int size = 3;
      
   	unsigned char pool[sizeof(Test) * size];
      
   	for (int i = 0; i < size; ++i) {
   		new (pool + (sizeof(Test) * i)) Test(i);
   	}
      
   	auto ptr = launder(reinterpret_cast<Test *>(pool));
      
   	for (int i = 0; i < size; ++i) {
   		destroy_at(ptr + i);
   	}
      
   	cout << __func__ << " end" << endl;
   }
      
   void destroy_n_test() {
   	cout << __func__ << " start" << endl;
      
   	constexpr int size = 3;
      
   	unsigned char pool[sizeof(Test) * size];
      
   	for (int i = 0; i < size; ++i) {
   		new (pool + (sizeof(Test) * i)) Test(i);
   	}
      
   	auto ptr = launder(reinterpret_cast<Test *>(pool));
      
   	destroy_n(ptr, size);
      
   	cout << __func__ << " end" << endl;
   }
      
   int main() {
   	destroy_test();
      
   	cout << endl;
      
   	destroy_at_test();
      
   	cout << endl;
      
   	destroy_n_test();
      
   	return 0;
   }
  

• 실행 결과

   destroy_test start
   ~Test() : 0
   ~Test() : 1
   ~Test() : 2
   destroy_test end
      
   destroy_at_test start
   ~Test() : 0
   ~Test() : 1
   ~Test() : 2
   destroy_at_test end
      
   destroy_n_test start
   ~Test() : 0
   ~Test() : 1
   ~Test() : 2
   destroy_n_test end