c++ - 两个指针存储的信息不同

Question

是否真的有:

int* p = new int;

和:

int* p1 = new int[5]();

如果是 p1，会存储额外的信息吗？

Answer 1

是的，可能有。

我建议您阅读以下内容以了解 C++-faq 中的项目:

• How does the compiler know there are n objects to be destructed using delete[] ?
• How do compilers use "over-allocation" to remember the number of elements in an allocated array ?

从第一个链接中提取的相关引用:

The run-time system stores the number of objects, n, somewhere where it can be retrieved if you only know the pointer, p. There are two popular techniques that do this. [...]

• Over-allocate the array and put n just to the left of the first Fred object.
• Use an associative array with p as the key and n as the value