调用临时对象的方法是安全的吗？ [英] Is it safe to call temporary object's methods?

问题描述

我有一个函数应该返回一个char *。因为我必须连接一些字符串，所以我写了以下行：

I have a function which shall return a char*. Since I have to concatenate some strings, I wrote the following line:

std::string other_text;
// ...
return ("text" + other_text).c_str();

我知道我可以避免命名我想要返回的字符串的问题。我只想借机会提出一个更一般的问题：
是否可以安全地调用临时变量的方法？是标准兼容吗？

I know that I could avoid the question naming the string I want to return. I just want to take the chance to make a more general question: is it safe to call methods of temporary variables? is it standard compliant?

推荐答案

调用临时变量的方法是安全的，但不安全返回临时变量的char * 。

It is safe to call methods of temporary variables, but not safe to return a char* of a temporary variable for later use.

这个char *指向一个即将释放的缓冲区。一旦释放，你将有一个指向内存中无效区域的指针。

This char* points to a buffer that will be freed soon. Once it is freed you will have a pointer to an invalid region in memory.

而是返回一个std :: string对象。

Instead please return an std::string object.

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