Just stop parsing when you encounter an unknown argument.
int done = 0;
while (!done && (option = getopt(argc, argv,"c:u:h")) != -1) {
switch (option) {
...
default:
done = 1;
break;
}
}
(or if you want, , use case '?':
instead of the default:
case,as getopt returns '?' when it encounters an unknown argument)