Pointer address memories belongs to RAM or Hard Drive?

Question

#include <stdio.h>
int main() {
    int num=1234;
    printf("%p", &num);
    return 0;
}

//Ouput:
//0xffffcbfc

Is 0xffffcbfc a RAM or a Hard Drive address memory?

https://stackoverflow.com/questions/5029938/c-pointers-and-the-physical-address — jeja, Sep 28 '17 at 09:30

score 6 · Answer 1 · answered Sep 28 '17 at 09:28

6

That code is, strictly speaking, exhibiting undefined behavior. You must convert the pointer to void * since that's what %p expects:

printf("%p\n", (void *) &num);

And it's probably unspecified from C's point of view exactly what kind of physical device holds the address, but on a typical computer it's going to be RAM.

answered Sep 28 '17 at 09:28

unwind

391,730
64
469
606

How to obtain a reference that express these topics. – EsmaeelE Sep 28 '17 at 11:54

score 1 · Answer 2 · answered Sep 28 '17 at 09:28

1

It's a stack address, which is notionally RAM. It won't be a real physical RAM address (in modern systems) and really only reflects the bookkeeping the kernel does.

answered Sep 28 '17 at 09:28

Joe

7,378
4
37
54

score 1 · Answer 3 · answered Sep 28 '17 at 09:29

1

Programs on computers that have a HD are always loaded into RAM by the OS and executed from there. All addresses will point at RAM.

You cannot address HD memory directly from the program, you'll have to go through the file system.

answered Sep 28 '17 at 09:29

Lundin

195,001
40
254
396

score 1 · Accepted Answer · answered Sep 28 '17 at 09:47

Strictly speaking, when printing the address of a variable the address you see is from the virtual memory (provided, in most cases you would be running your program on an OS which uses virtual memory).

If your OS does not use a virtual memory, the address would be directly from the RAM.

To run a program, you have to load it into memory (RAM). In short, you will not get an address from your hard drive.

Pointer address memories belongs to RAM or Hard Drive?

4 Answers4