Subject: Re: [boost] Towards a Warning free code policy proposal
From: Bo Persson (bop_at_[hidden])
Date: 2010-08-28 05:53:57
John Maddock wrote:
>
> I'm completely against disabling warnings in such a blanket manner
> for a number of reasons:
>
> 1) It doesn't fix anything, it hides it.
> 2) I have found legitimate bugs in both my code and others as a
> result of fixing what looked to be "busy-body" warnings at first
> glance. Unfortunately, not all have been fixed: for example
> https://svn.boost.org/trac/boost/ticket/3606
> 3) As others have noted, some warnings are only emitted when a
> template is instantiated with certain template arguments - in this
> case the warning may be telling the user something important about
> the template arguments that they're using and *should be seen*.
> 4) Blanket disabling does nothing for compilers that don't have such
> mechanisms - indeed I would contend that it would make things
> worse, as the trend would be towards "don't worry about warnings".
> 5) I worry that this would lead towards poorer quality code and an
> "out of sight out of mind" mentality.
> 6) As a last resort, we can always resort to - preferably selective
> - disabling methods when all else fails.
>
> So... yes we need to do something about warnings, and yes I would
> like to see our tests run with "warnings as errors" for some
> compilers at
> least, but please not like this!
>
> Anyhow, I'll jump down off my soap box now ;-)
>
> John
>
I totally agree with this.
When targeting a specific compiler, a 3rd party library can use
non-standard but implementation defined behavior. You cannot use
implementation specific behavior, especially not if it is
undocumented.
The implementor of a specific compiler's standard library can, and
probably must, use these extensions. However, when they are "granted
on an ad-hoc basis"
http://gcc.gnu.org/onlinedocs/cpp/System-Headers.html
it would be extremely dangerous for anyone else to rely on these
features. How do we know exactly what they are, or when they change?
Bo Persson