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Re: Re: Should a disabled warning be allowed to be promoted to an error(Bugzilla PR 70275)?

I apologize for stating that you had reported the issue.  I copy/pasted from your comment rather than the original report.
The issue was reported by Teodor Petrov 


---- "Manuel LÃpez-IbÃÃez" <> wrote: 
> > On 03/28/2016 01:56 PM, Florian Weimer wrote:
> >>> In Bugzilla PR # 70275, Manuel LÃpez-IbÃÃez reports that even though
> >>> he provides the "-Werror=return-type" option, the compiler doesn't
> >>> flag the warning/error about a control reaching the end of a non-void
> >>> function, due to the presence of the "-w" option.  He points out that
> >>> clang++ wtill flags the promoted warning even though warnings are
> >>> inhibited.
> I did not report the bug and did not mention anything of the above. I only 
> commented on why GCC works like it works and how one can change the behaviour 
> if so desired. I don't care one way or the other and I can see benefits for 
> either behaviour.
> >> I think -w is ordered with respect to the other warning obtions, and
> >> -w inhibits previously requested warnings, and future -W flags may
> >> enable other warnings.  With this in mind, I agree that the current
> >> GCC behavior is consistent and probably not a bug.
> The command-line order does not affect '-w' and there is no way to undo '-w'. 
> It is a global boolean switch independent of anything else (including pragmas) 
> that disables warnings just before they are re-classified (by pragmas or 
> -Werror=) into something else. This means that if -Wfoobar is given in the 
> command-line (or enabled by a pragma) and it requires an expensive analysis, 
> this analysis is done even in the presence of -w, only the warning message is 
> not emitted.
> One question to answer if the behaviour does change is what would be the effect 
> of using '-w' on warning options enabled by #pragmas. Some people may still 
> want a switch that simply disables all warnings no matter how they are enabled.
> Cheers,
> 	Manuel.

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