[erlang-questions] Kill a process tree

[June Kim]

Suppose I spawned a process and let's call it "root".

root will probably spawn a few children, and those children, in turn,
would spawn a few grand-children.

Now, I want to kill the process tree starting from root. How can I achieve it?

Limitation: the thing is that all the code is written using plain
spawn and no consideration was done in the code for this kind of
case(such as link). Moreover, you can't change the code. The code for
root and so on were written without any regard for this process tree
kill. (well, suppose the root and its descendant codes were written by
a third-party)

How can I do it?

June