尝试访问空指针 [英] Attempting to access a null pointer

问题描述

#include <iostream>

int main()
{
    int* i = 0;
    int x = (*i);
    std::cout << x;
}

当我使用Visual Studio 2010编译并运行上述程序时，该程序将崩溃，并且我知道它会崩溃，因为我将指针设置为0.

The above program will crash when I compile and run it using Visual Studio 2010 and I know it crashes because I set the pointer to 0.

我想知道的是，使用标准中定义的C ++访问null pointer还是未定义，我只是很幸运，由于我的编译器/计算机/操作系统，我的程序崩溃了

What I would like to know, is accessing a null pointer in C++ defined in the standard or is it undefined and I just happen to get lucky that my program crashed because of my compiler/computer/operating system

如果已定义，当我尝试访问空指针时，C ++可以保证我什么?

If it is defined, what does C++ guarantee me when I try and access a null pointer?

推荐答案

取消引用空指针将调用未定义的行为.它可能在不同的编译器上产生不同的结果，甚至更多-如果多次编译，同一编译器上可能会发生不同的事情.完全不能保证行为.

Dereferencing a null pointer will invoke undefined behavior. It may result in different things on different compilers, even more - different things may happen on the same compiler if compiled multiple times. There are no guarantees of the behavior at all.

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