(amd64)ubuntu@localhost:~$ echo 3 | sudo tee /proc/sys/vm/drop_caches
3
(amd64)ubuntu@localhost:~$ ./time ./w4n 
0.00user 0.00system 0:00.01elapsed 0%CPU (0avgtext+0avgdata 1724maxresident)k
1968inputs+0outputs (4major+248minor)pagefaults 0swaps
(amd64)ubuntu@localhost:~$ ./time ./cw4n 
0.00user 0.00system 0:00.00elapsed 0%CPU (0avgtext+0avgdata 1160maxresident)k
24inputs+0outputs (0major+73minor)pagefaults 0swaps
(amd64)ubuntu@localhost:~$ ./time ./wait4network 5s
0.00user 0.00system 0:00.01elapsed 53%CPU (0avgtext+0avgdata 1960maxresident)k
3128inputs+0outputs (16major+291minor)pagefaults 0swaps