在printf的C程序的当前地址 [英] Printf the current address in C program

问题描述

想象一下，我有以下简单的C程序：

Imagine I have the following simple C program:

int main() {

int a=5, b= 6, c;
c = a +b; 
return 0;
}

现在，我想知道前任pression的地址C = A + B，即程序地址
其中，此加法进行。是否有可能，我可以用printf？
沿线的东西：

Now, I would like to know the address of the expression c=a+b, that is the program address where this addition is carried out. Is there any possibility that I could use printf? Something along the line:

int main() {

int a=5, b= 6, c;
printf("Address of printf instruction in memory: %x", current_address_pointer_or_something)
c = a +b; 
return 0;
}

我知道我怎么能使用GDB，然后信息行file.c中找到的地址了：行。然而，我知道，如果我还可以借助printf直接做到这一点。

I know how I could find the address out by using gdb and then info line file.c:line. However, I should know if I could also do that directly with the printf.

推荐答案

在GCC，你可以使用＆放取标号的地址;＆安培;运营商。所以，你可以这样做：

In gcc, you can take the address of a label using the && operator. So you could do this:

int main() 
{
    int a=5, b= 6, c;

    sum:
        c = a+b;

    printf("Address of sum label in memory: %p", &&sum);
    return 0;
}

＆安培的结果;＆安培;总结是，如果你做了一个转到款项，将被发射的跳转指令的目标。所以，虽然这是真的，有一个在C / C ++没有一个人对一地址到在线地图，你还可以说给我一个指向此code。

The result of &&sum is the target of the jump instruction that would be emitted if you did a goto sum. So, while it's true that there's no one-to-one address-to-line mapping in C/C++, you can still say "get me a pointer to this code."

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