How to make child process die after parent exits?

Question

Suppose I have a process which spawns exactly one child process. Now when the parent process exits for whatever reason (normally or abnormally, by kill, ^C, assert failure o

Answer 1

If you send a signal to the pid 0, using for instance

kill(0, 2); /* SIGINT */

that signal is sent to the entire process group, thus effectively killing the child.

You can test it easily with something like:

(cat && kill 0) | python

If you then press ^D, you'll see the text "Terminated" as an indication that the Python interpreter have indeed been killed, instead of just exited because of stdin being closed.