Build portability: enable or disable warnings

[Dr Andrew John Hughes]

On 07:25 Mon 16 May     , Erik Trimble wrote:
> On 5/16/2011 6:03 AM, Andrew Haley wrote:
> > On 05/16/2011 12:08 PM, Dalibor Topic wrote:
> >
> >> The reason I'm asking is that I'm wondering if this is something we
> >> should expect to crop up in different parts of the code base, or
> >> whether it's a one off due to some specific thing some distros chose
> >> to do different from each other.
> > That's hard to say.  It certainly could crop in other parts of the
> > code base, and I'm surprised it doesn't happen regularly.  I'm rather
> > appalled that distros do this kind of thing, TBH.
> >
> > Andrew.
> 
> 
> Just so I understand this - you're saying that by running *just* the 
> 'gcc' command on different linux systems, that actually implies that gcc 
> gets invoked with some set of flags already set? And, that there's no 
> way to just invoke "vanilla" gcc ?
> 
> If so, that's, ah, mindboggling (not in a good way)...
> 

Maybe I'm misreading what you said, but I don't find it mindboggling that
an application would have default settings for certain options.  That's
basically what we're talking about here.  If a warning can be either on
or off, then one of these two has to be a default for that exact situation
when the user does just say "gcc" and doesn't specify whether they want
the warning or not.

A number of distros change the defaults of gcc in order to produce more
warnings, as some can point to real security issues.  This runs afoul of
HotSpot's use of -Werror which presumably assumes the default set of
warnings used by a certain version of gcc.  I think the appropriate solution
to this is, as Andrew suggests, to make explicit our preference for that
warning rather than relying on the implicit defaults.

> -- 
> Erik Trimble
> Java System Support
> Mailstop:  usca22-123
> Phone:  x17195
> Santa Clara, CA
> Timezone: US/Pacific (GMT-0800)
> 

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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