-isystem vs. #pragma system_header

[Nathan Myers]

On Wed, May 17, 2000 at 08:13:26PM -0700, Zack Weinberg wrote:
> On Wed, May 17, 2000 at 06:48:40PM -0700, Nathan Myers wrote:
> > I am concerned that with the new pragma it may become harder to control
> > warning behavior on header files.  E.g., users don't ever want warnings 
> > about system headers, but when we are developing we do want warnings.  
> > Ideally, the headers would not have anything in them to warn about,
> > but we have to sub-include vendor headers we have no control over.
> > 
> > This can be solved ...
> > by adding (yet) another "-W" option to control how the compiler emits
> > warnings for system headers.
> 
> I could trivially add a -fno-system-headers or something like that
> that shut off all special treatment for system headers.  Anything more
> complex than that is going to need careful discussion.

Maybe it should be -Wsystem-headers, instead: issue warnings about 
constructs even in system headers.  I have an idea that knowing it's 
a system header will be interesting for other reasons, so you won't 
want to turn it off just to be able to see warnings.

Nathan Myers
ncm at cantrip dot org