[PATCH] PR18327: -Wsystem-headers introduces build errors

[Argyrios Kyrtzidis]

On Jan 7, 2014, at 7:56 PM, Alp Toker <alp at nuanti.com> wrote:

> 
> On 08/01/2014 01:48, Argyrios Kyrtzidis wrote:
>> On Jan 6, 2014, at 1:47 PM, Richard Smith <richard at metafoo.co.uk <mailto:richard at metafoo.co.uk>> wrote:
>> 
>>> One view on this is simply: -Wsystem-headers means "don't give system headers special treatment when emitting diagnostics”.
>> 
>> This is it exactly. “Treat all headers like normal headers"
> 
> We don't have a flag to treat all headers as normal headers at the moment. It'd be very simple to implement compared to -Wsystem-headers which somewhat intricate.

Could you elaborate, AFAICT '-Wsystem-headers' is treated specially, it's outside the diagnostic group machinery, and acts essentially as a flag.
If you'd like to have something like '-fwarn-on-system-headers' or something instead, that's another discussion, but as far as the PR is concerned I don't see why we need to change what -Wsystem-headers is currently doing.

> 
> Alp.
> 
>> 
>>> That would seem to make perfect sense to people developing system headers, and is our current behavior. What is the use case that leads to enabling -Wsystem-headers but not wanting that to lead to errors? PR18327 doesn't make that obvious.
>> 
>> Not sure I’m following that report, if one doesn’t like that that diagnostic is by default mapped to an error, maybe map it to a warning on the command-line or discuss whether it should not be mapped to error by default ?
>> I don’t see a need to complicate what -Wsystem-headers does.
>> 
> 
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