[erlang-questions] How to clean up before termination...

[Dawid Figiel]

Hi,

There is a recommendation in Erlang doc, which is telling to set up
the trap_exit to true in the gen_server:init, when want to do clean up
before supervisor will terminate the gen_server.

http://www.erlang.org/doc/design_principles/gen_server_concepts.html#id66567

My question is:
What for trap_exit has to be set to true when the clean up is needed?

The place for doing some clean ups is under terminate function.
We want to have trape_exit set to true when we need to handle 'EXIT'
signals coming from linked processes to (for example) not crash
gen_server.

The only explanation for me is that the supervisor may crash too and
send 'Exit' to gen_server as well... but this doesn't convince even
myself.

Has anyone some explanation for this advice ?


Best,

Dawid