1#include <stdint.h> 2 3volatile uint64_t x; 4 5int main(int argc, char *argv[]) 6{ 7 uint64_t old, new = argc; 8 9 argv = argv; 10 do { 11 old = __sync_val_compare_and_swap(&x, 0, 0); 12 } while (!__sync_bool_compare_and_swap(&x, old, new)); 13 return old == new; 14} 15