If you happen to target Windows platform (I know article does not), don't reinvent the wheel. There are NT Job Objects [1] for this. The 'target' process creates the job with `JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE` set and keeps the job handle open. 'dependend' processes (by default all children spawned by 'target', but you can add more) will all be killed when the 'target' process terminates, no matter how is terminated. Jobs can do more, like cap CPU/IO/Memory for the job.

[1] https://msdn.microsoft.com/en-us/library/windows/desktop/ms6...