in reply to SIG{INT} not handling CTRL-C ???

This code doesn't seem to do what you'd expect it to do...At least, it doesn't hang around and wait for your CTRL-C. The only thing it does is spawn 3 children right away and then exiting. This is done quite quickly and I'm guessing any CTRL-C's you do press afterwards are just sent to whatever shell you're executing the code from.
If you add a sleep 300; after your child_fork();-call, you'll have more time to see that the CTRL-C is indeed handled the way you wanted.