使用函数指针变量的地址将函数指针分配给函数

Question

I have a function pointer defined like below:

typedef void (*FPT)(void);
FPT Fp;

The pointer variable "Fp" is located at address 0x1234 I have my function defined like below:

void myfunc (void)
{
    return;
}

I do not have access to the symbol name "Fp" but I know its address (0x1234). Now how do I assign the address of myfunc() to "Fp" ??

Answer 1

This should do what you want.

FPT *fpt_pointer = (FPT *)0x1234;

*fpt_pointer = myfunc;

But note that it's very bad practice to have hard coded addresses like this. I don't know whether you really intend to do that (don't!) or whether you are just describing it that way to simplify the question. It is very likely to break the next time you run the program (even without a re-compile due to Address Space Layout Randomisation).