[erlang-questions] erlang:trace/3

[Emilio De Camargo Francesquini]

Hello,

I'm having some trouble understanding the exact meaning of two of the
flags for the erlang:trace/3 function.

Flag:

- running
    Trace scheduling of processes.
    Message tags: in, and out.

I imagine that a message tagged "in" means that the process was chosen
by a scheduler and will begin/resume execution and a tag "out" means
that the processes has been preempted. Is that correct?


- exiting
    Trace scheduling of an exiting processes.
    Message tags: in_exiting, out_exiting, and out_exited.

I guess that these messages are sent when the proccess is about to
exit or has already exited. Am I right? What is the exact difference
between each one of them?

Moreover, what is the difference between "exiting" flag with the tag
"out_exited" and "procs" flag with the tag "exit"?

Thanks!