参考变量存储在哪里 [英] Where does the reference variable gets stored

问题描述

我知道引用不会占用任何内存，它将指向它所引用的相同内存位置.例如

I know that reference does not take any memory it will point to the same memory location which it is referencing. for eg

int i=10;
int &r = a;

假设 i 指向存储位置1000，因此在这种情况下， r 也将指向存储位置1000.但是在C ++中，每当我们声明一个变量时，它将被存储在内存中的某个位置.在这种情况下， r 指向某个位置，但应通过某种内部表示将其存储在内存中的某个位置.预先感谢.

suppose i points to the memory location 1000 so in this case r will also point to the memory location 1000. But in C++ whenever we are declaring a variable it will get stored in the memory at some location. In this case r is pointing to some location but it should be stored somewhere in memory via some internal representation. thanks in advance.

推荐答案

这是未指定的，这是有充分理由的.真正的答案是:它取决于参考.它可以表示为普通指针，也可以根本不存在.

That is left unspecified, and for good reason. The real answer is: it depends on the reference. It can be represented as a normal pointer, or it may not exist at all.

如果您具有自动存储持续时间的本地函数引用，例如 r :

If you have a function-local reference with automatic storage duration, such as this r:

void foo()
{
  int x[4] = {0, 1, 2, 3};
  int &r = x[1];
  // more code
}

那么它可能根本不会占用任何空间.编译器将简单地将 r 的所有使用作为 x [1] 的别名，然后直接访问该 int .请注意，此类别名样式引用也可以由函数内联产生.

then it will probably not take up any space at all. The compiler will simply treat all uses of r as an alias for x[1], and access that int directly. Notice that such alias-style references can also result from function inlining.

另一方面，如果引用是持久的"或对其他翻译单元(例如数据成员或全局变量)可见，则它必须占用一些空间并存储在某个地方.在这种情况下，它很可能会表示为指针，并且使用该代码的代码将被编译为取消对该指针的引用.

On the other hand, if the reference is "persistent" or visible to other translation units (such as a data member or a global variable), it has to occupy some space and be stored somewhere. In that case, it will most likely be represented as a pointer, and code using it will be compiled to dereference that pointer.

从理论上讲，也可以使用其他选项(例如查找表)，但我认为这些选项都不会被任何现实世界的编译器使用.

Theoretically, other options would also be possible (such as a lookup table), but I don't think those are used by any real-world compiler.

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