From: Ken Bloom <kbloom@...>
Date: 2008-04-16T02:10:31+09:00
Subject: Re: at_exit handlers and Process.kill

On Tue, 15 Apr 2008 11:28:33 -0500, Daniel Berger wrote:

> ts wrote:
>> Daniel Berger wrote:
>>> # process_test.rb
>>> File.open("pid.txt", "w"){ |fh| fh.print Process.pid } p Process.pid
>>>
>>> sleep 1 while true
>> 
>>  you really think that the following line will be executed ?
> 
> Why not? The docs say at_exit, "Converts block to a Proc object (and
> therefore binds it at the point of call), and registers it for execution
> when the program exits."

Ruby does *everything* in the order it encounters it in the file.
at_exit installs an exit handler, (a proc to be run later) but it's a 
method that has to be executed. If you put "sleep 1 while true" before 
the at_exit call, the at_exit call will never be executed, so the exit 
handler will never be installed. Adjust your program to call at_exit (or 
whatever other handlers you want) before running anything else.

# process_test.rb
at_exit {
    puts "AT_EXIT"
}

END{
    puts "END"
}

trap("KILL"){
    puts "KILLED"
}


File.open("pid.txt", "w"){ |fh| fh.print Process.pid }
p Process.pid

sleep 1 while true

--Ken

-- 
Ken (Chanoch) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/