Re: Config_Files proposal

[Ted Dennison <dennison@telepath.com>]

Stephen Leake wrote:
> Darren New <dnew@san.rr.com> writes:
> 
>>But you can eliminate a large number of race conditions by implementing a
>>merge. You can change it from "if you start the same program twice, you're
>>screwed" to "if you click the button on both instances in the length of time
>>it takes to write the file, you're screwed." I think that's reasonable. 

I think when they fixed the Emacs ada-mode case exceptions file writing 
algorithm, they did something like this. I was satisfied at the time, 
for the exact reason Darren mentions.

> 
> Right, I don't. I tend to be very picky; a file locking protocol is
> either "right", or it's "wrong"; no room for "mostly right" :).

I'd have to agree with this. For a single application like Emacs, it may 
be good enough to come close. For something that is going to be an 
official part of Ada, I don't think we should put in a feature that 
proports to solve a problem that it doesn't actually solve.

> It is smaller, but I'm willing to bet someone will hit it. For
> example, when you shutdown the computer, all the active editor
> instances will write to the config file at once. Maybe us "real"

Exactly. And when someone gets this problem, hoses their config file 
that they had setup *juuuust* right, and tracks the problem down, they 
are going to be quite ticked that the language advertised something as 
safe when it in fact wasn't.

> programmers don't leave editors active when we shutdown, but a lot of
> people do!

Actually, I would probably not have that happen to me, just because I 
never purposely shut my systems down. They only way they go down is the 
hard way. :-)