Finding out when a process has died

[MK]

Hi,

I want to write a process (hopefully userspace) which will "watch"
other processes and do something when a process dies. What is a good
way to do this? A simple solution would be to have a stream/tcp
connection between the watcher and other processes and when the
connection is broken, you know the other side has died. Is there a
better way to do this possibly involving a kernel mod?

Thanks!!