在C ++中使用delete删除malloc的行为 [英] Behaviour of malloc with delete in C++

问题描述

int *p=(int * )malloc(sizeof(int));

delete p;

当我们使用malloc分配内存时，我们应该使用free释放它，当我们使用C ++然后我们应该使用删除。

When we allocate memory using malloc then we should release it using free and when we allocate using new in C++ then we should release it using delete.

但是如果我们使用malloc分配内存，然后使用删除，那么应该有一些错误。但是在上面的代码中没有C ++中出现的错误或警告。

But if we allocate memory using malloc and then use delete, then there should be some error. But in the above code there's no error or warning coming in C++.

此外，如果我们使用new来释放和释放，那么也没有错误或警告。

Also if we reverse and allocate using new and release using free, then also there's no error or warning.

为什么会这样？

推荐答案

因为没有办法可靠地证明指针后面的内存被正确分配了（例如 new for delete 或 new [] for delete [] ）。这是你的工作，以确保这样的事情不会发生。当你使用正确的工具，即智能指针，它很简单。每当你说 delete ，你就做错了。

This is undefined behaviour, as there's no way to reliably prove that memory behind the pointer was allocated correctly (i.e. by new for delete or new[] for delete[]). It's your job to ensure things like that don't happen. It's simple when you use right tools, namely smart pointers. Whenever you say delete, you're doing it wrong.

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