c pointers - warning format '%x' expects arguments of type 'unsigned int'

Question

I'm currently reading Hacking the art of exploitation and there is an example on there that I cannot seem to get correct. Attempting to compile results in the error:

./addressof.c: In function ‘main’:
./addressof.c:8:4: warning: format ‘%x’ expects argument of type ‘unsigned int’,
but argument 2 has type ‘int *’ [-Wformat]


#include <stdio.h>
int main() {
   int int_var = 5;
   int *int_ptr;

   int_ptr = &int_var; // Put the address of int_var into int_ptr.

   printf("int_ptr = 0x%08x\n", int_ptr);
   printf("&int_ptr = 0x%08x\n", &int_ptr);
   printf("*int_ptr = 0x%08x\n\n", *int_ptr);

   printf("int_var is located at 0x%08x and contains %d\n", &int_var, int_var);
   printf("int_ptr is located at 0x%08x, contains 0x%08x, and points to %d\n\n",
      &int_ptr, int_ptr, *int_ptr);
}

I understand where the error is, I'm just not sure how to fix this.

Answer 1

The format specifier for pointer is %p, not %x. (See here)