Detect death of parent process

Question

How can I detect parent process death in Linux OS?

If in parent process called fork(), that create child process. In the parent process I can use system

Answer 1

In my Ubuntu 16.04.1 LTS getppid() returns no "1" but id of process "/sbin/upstart --user" after parent kill, so checking getppid() == 1 will not work and getppid() should be saved at child start and later compared.