Event driven programming can be done quite easily without tracking the time. You may want to revise your input/output design though. You can still use the command-line arguments, but once main exits, the user will need to run the program again.
So you need to ask the user explicitly if he wants to quit, and then return from main. Depending on your design it can be as simple as this while loop:
Code:
int mode;
while( (mode = getchar()) != 'x') {
puts("Checking server.");
checkserver();
fputs("Quit? ", stdout);
}