I'm not sure about the CNTRL-C being the best or easiest way to stop the process being run by open3. IPC::Open3 returns a PID, so what you might want to try is intercept the CNTRL-C in the parent, then use Proc::Killfam to killfam 9, $pid;

The killfam is used to get all shells and children related to the $pid in question. Often, the $pid returned by open3, is just a shell used to run your actual program.

Here is how to grab cntrl-c in your main.

# intercept CNTRL-C , kill open3, exit
$SIG{INT} = sub { killfam 9,$pid;  exit(0) };
[download]

You can google for many examples of using Proc::Killfam, I won't repeat them here.