#include <stdatomic.h>
#include <stdio.h>

int main(void)
{
	_Atomic int foo;
	_Atomic int * ptr;

	foo = 42;
	printf("foo: %d\n", foo);

	atomic_init(&ptr, &foo);
	printf("ptr: %p\n", ptr);
	printf("ptr: %d\n", *ptr);

	int r = atomic_exchange(ptr, 4242);
	printf("ptr: %p\n", ptr);
	printf("ptr: %d\n", *ptr);
	printf("r: %d\n", r);
}