Is it possible to save a memory address to a string?

Question

Say I have an object

MyObj stuff;

To get the address of stuff, I would print

cout << &stuff << endl; 0x22ff68

I want to save 0x22ff68 in a string. I know you can't do this:

string cheeseburger = (string) &stuff;

Is there a way to accomplish this?

To know if I've seen a particular object before. Does it matter? — , Apr 10 '12 at 15:43
It matters because what you are trying to do is nonesense really. — Alok Save, Apr 10 '12 at 15:44
If you "want to know if you've seen an object before" you'd just ... keep the memory address handy. Why would you convert it to a string? — Brian Roach, Apr 10 '12 at 15:45
It's complicated and I'm not posting a whole API on stack overflow :) — , Apr 10 '12 at 15:48
@a fish who swims around, I experience this with every question I post on stackoverflow. — , Apr 10 '12 at 15:59

score 11 · Answer 1 · answered Feb 10 '19 at 21:19

Here's a way to save the address of a pointer to a string and then convert the address back to a pointer. I did this as a proof of concept that const didn't really offer any protection, but I think it answers this question well.

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int main()
{
    // create pointer to int on heap
    const int *x = new int(5);
        // *x = 3; - this fails because it's constant

    // save address as a string 
    // ======== this part directly answers your question =========
    ostringstream get_the_address; 
    get_the_address << x;
    string address =  get_the_address.str(); 

    // convert address to base 16
    int hex_address = stoi(address, 0, 16);

    // make a new pointer 
    int * new_pointer = (int *) hex_address;

    // can now change value of x 
    *new_pointer = 3;

    return 0;
}

score 10 · Accepted Answer · edited May 23 '17 at 11:47

10

You could use std::ostringstream. See also this question.

But don't expect the address you have to be really meaningful. It could vary from one run to the next of the same program with the same data (because of address space layout randomization, etc.)

edited May 23 '17 at 11:47

Community

1
1

answered Apr 10 '12 at 15:44

Basile Starynkevitch

223,805
18
296
547

1

I understand that. It only needs to be correct for current run. Thank you! – Apr 10 '12 at 15:51

score 5 · Answer 3 · answered Apr 10 '12 at 15:48

You can try using a string format

char strAddress[] = "0x00000000"; // Note: You should allocate the correct size, here I assumed that you are using 32 bits address

sprintf(strAddress, "0x%x", &stuff);

Then you create your string from this char array using the normal string constructors

Is it possible to save a memory address to a string?

3 Answers3

Linked