From: Joel VanderWerf <vjoel@...>
Date: 2008-04-16T02:22:23+09:00
Subject: Re: at_exit handlers and Process.kill

Ken Bloom wrote:
> 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.

Note that you can use BEGIN to register handlers out of order:

exit

BEGIN {
   at_exit { puts "at_exit" }
   END { puts "END" }
}


(without the BEGIN, nothing is printed)


-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407