Two string literals have the same pointer value?

Question

When I run this program using MinGW, im getting output as \"=\"

#include

using namespace std;

int main()
{
 char *str1 = \"Hello\";
 char *         


        

Answer 1

This is an expected result. You can verify this by looking at the underlying assembly. For example, if I build with:

g++ -S ptr.c

then you can see the following in the file output (ptr.s):

        .file   "ptr.c"
        .def    ___main;        .scl    2;      .type   32;     .endef
        .section .rdata,"dr"
LC0:
        .ascii "Hello\0"               ; Note - "Hello" only appears once in
                                       ; this data section!
LC1:
        .ascii "=\0"
LC2:
        .ascii "!=\0"
        .text
.globl _main
        .def    _main;  .scl    2;      .type   32;     .endef
_main:
        [... some stuff deleted for brevity ...]
LCFI5:
        call    ___main
        movl    $LC0, -12(%ebp)        ; This sets str1
        movl    $LC0, -8(%ebp)         ; This sets str2
        movl    -12(%ebp), %eax

I've commented the two key bits -- only one appearance of 'Hello' is in the rdata section of the underlying code, and you can see str1 and str2 are set towards the end, both pointing to the same label: LC0. This is beacuse 'Hello' is a string literal and, importantly, is constant.

As others have pointed out - this is perfectly legal under the standards.