放置新和删除 [英] placement new and delete

问题描述

什么是正确的方法来删除这里分配的所有内存？

What is the right method to delete all the memory allocated here?

  const char* charString = "Hello, World";
  void *mem = ::operator new(sizeof(Buffer) + strlen(charString) + 1);
  Buffer* buf = new(mem) Buffer(strlen(charString));

  delete (char*)buf;

或

  const char* charString = "Hello, World";
  void *mem = ::operator new(sizeof(Buffer) + strlen(charString) + 1);
  Buffer* buf = new(mem) Buffer(strlen(charString));

  delete buf;

或两者是否相同？

推荐答案

正确的方法是：

buf->~Buffer();
::operator delete(mem);

您只能使用 delete em>运算符中接收到的 运算符。如果直接调用 operator new 函数，您还必须直接调用 operator delete 函数，并且必须手动调用析构函数。

You can only delete with the delete operator what you received from the new operator. If you directly call the operator new function, you must also directly call the operator delete function, and must manually call the destructor as well.

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