Question: Const var defining another const var

Hi there.

Could anyone please explain to me why, when I compile the following code with GCC I got an error?
Code:

Code:

---

#include <stdio.h>

const int CONSTANT_1 = 3;
const int CONSTANT_2 = CONSTANT_1 + 2;

int main (void) {

    printf("Constant 2 is: %d\n", CONSTANT_2);

    return 0;
}

---

The error I got is:
"test_const.c:4:1: error: initializer element is not constant
const int CONSTANT_2 = CONSTANT_1 + 2;"

When I run it in CLANG it works fine.

It also work (in GCC and CLANG) when in declare the constants inside the main function.

Thanks in advance.

See top answers here and here.

I must admit I thought that would be valid integer constants... I'm a little disappointed that an integer constant isn't really "constant". I think I read somewhere that using an enum type is better than using "const" in these cases, but I have to admit I've not ran into this problem myself...

Thanks for the answer.