What Happens if We Don't Wait for a Child?

A zombie (also called: ghost) process is a terminated process but not waited upon by its parent.

Zombie/ghost processes continue to consume small portion of the operating system’s resources.

Be a responsible parent: if you

fork()

a child process, you must

wait()

on the child – even if you don't care about the child's return status.

But what happens if the parent dies before the child? Whenever a process terminates, the kernel walks its children and re-parents them to the init process. (Bonus question: what is the

pid

of init?)

The init process periodically waits on all its children and allows them to exit normally and fully, ensuring zombies don't live for long and, therefore, don't take up valuable OS resources.