c_str（）真正返回的是什么 [英] What c_str() really returns

问题描述

我对成员函数string :: c_str（）感到困惑。

它是否创建了一个新的char数组，复制内容然后返回初始元素的指针？或只是一个指向已经创建的数组的指针？

但是如果是这样，为什么像下面那样的代码不会破坏字符串对象？

I have a confusion with the member function string::c_str().
Does it create a new char array, copies the contents then returns the pointer of the initial element ? or just a pointer to the already created array ?
But if so, why a code like the one below won't destroy the string object?

string s = "Hi Sam";
const char *c = s.c_str();
delete c;

谢谢，山姆。

Thanks, Sam.

推荐答案

这是真的是一个问题，你应该解决自己bei谷歌搜索回答。



解释意味着它返回指向对象内部字符串的指针。所以它不是一个新的对象或内存块。



使用调试器的详细视图来查看对象的内部内容。

This is really a question you should solver yourself bei googling for the answer.

Explained means it, that it returns the pointer to the inner string of the object. So it is NOT a new object or memory block.

Use the detail view of your debugger to see the inner guts of objects.

您提供的代码可以在C ++程序中执行任何操作 - 其行为未定义。



那么是什么原因使它未定义？在这种情况下有两件事：



- 你正在删除一些尚未被新分配的东西

- 你要删除一个数组使用错误的删除形式



所以除非一个类的合同告诉你要删除一些东西，否则不要！

The code you presented could do just about anything in a C++ program - its behaviour is undefined.

So what makes it undefined? Two things in this case:

- you're deleting something that hasn't been allocated by new
- You're deleting an array using the wrong form of delete

So unless the contract for a class tells you to delete something, DON'T!

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