51 std::atomic_int test1(0);  variable
59   assert(test1 == 0);  in f1()
61   while (test1 == 0)  in f1()
64   assert(test1 == 1);  in f1()
65   test1 = 2;  in f1()
91     test1 = 1;  in main()
100     if (test1 == 2) {  in main()
103       test1 = 0;  in main()
105       assert(test1 == 1);  in main()
117     if (test1 == 2) {  in main()
120       test1 = 0;  in main()
122       assert(test1 == 0);  in main()