c++ - 变量在堆栈上是连续的吗？

Question

我想知道下面代码中的数组 a 和 b 在内存中是否连续：

int main() {
    int a[3];
    int b[3];

    return 0;
}

a[0],a[1]并且a[2]对于 应该是连续的和相同的，但是对于将分配到b哪里有任何保证吗？ba

如果没有，有什么方法可以强制a和b彼此相邻吗？即，以便它们在堆栈中彼此相邻分配。

Answer 1

不，C++ 不保证这些变量在内存中的位置。一个或两个甚至可能不在内存中（例如，如果它们被优化了）！

In order to obtain a relative ordering between the two, at least, you would have to encapsulate them into a struct or class and, even then, there would be padding/alignment to consider.

Answer 2

There's no guarantee that individual variables will be next to each other on the stack.

In your example you could "cheat" and simulate what you're looking for by doing this:

int main() 
{
    int buffer[6]
    int *a = buffer;
    int *b = buffer+3;

    return 0;
}

Now, when you write to a[4] you'll actually write to b[0].