test.c

#include <stdio.h>

char a[] = "foo\n";
char b[] = "bar\n";
char *c[] = {
  a,
  b
};

// prints: "foo\n" as expected, no compile warnings
//int main() {
//  printf("%s", c[0]);
//};

// doesn't work
char *d = c[0];
int main() {
  printf("%s", d);
}

// test.c:16:11: error: initializer element is not a compile-time constant
// char *d = c[0];
//           ^~~~
// 1 error generated.