使用& （addressof）与C中的const变量 [英] Using & (addressof) with const variables in C

问题描述

教科书上说& （addressof）运算符不适用于无法应用于表达式，
常数或寄存器变量。

常数仅表示诸如'A'，'7'等常量还是

我认为这只意味着文字，因为以下代码可以编译：-

Text books say that & (addressof) operator doesn't apply to cannot be applied to expressions,
constants, or register variables.
Does constants mean only literals like 'A', '7' etc or variables declared with const keyword as well?
I think this mean only literals since following code compiles:-

int main()
{
const int i=10;
const int *ip;

ip = &i;

}

推荐答案

否-可以将其应用于限定为 const 的变量。但是请注意，这样做（通常）意味着编译器必须实际为该变量分配一个地址-如果仅以不需要地址的方式使用该地址，则使用 const 变量通常根本不需要分配任何存储空间（即，使用 const 变量生成的代码通常几乎就像您使用a直接输入文字，但您的源代码却改用了有意义的名称。）

No -- it can be applied to a variable that's qualified as const. Note, however, that doing so (generally) means that the compiler has to actually assign that variable an address -- if you only use it in ways that don't need an address, a const variable often won't need to be assigned any storage at all (i.e., the code generated using a const variable will often be almost like you'd use a literal directly, but your source code gets to use a meaningful name instead).

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