From: Daniel Berger <djberge@...>
Date: 2005-05-14T06:05:22+09:00
Subject: Customing the Exception class

Hi all,

I have a program where I want to send all errors to a file.  So, I did this:

class Exception
    alias :old_init :initialize
    def initialize(arg)
       old_init(arg)
       File.open("log.txt","a+"){ |fh| fh.puts("Error: #{arg}") }
    end
end

This works for most errors, but it doesn't seem to work when the error 
is a SystemCallError.

For example, this writes to the log as expected:

print "Some crazy division: "
p 1/0

But this does not:

File.open("non-existant file")

The latter raises an Errno::ENOENT.

Why, if SystemCallError is a subclass of Exception, does my approach not 
work?  How do I make this work as expected?

Regards,

Dan