Re: Patch -Wtraditional, warn about `U' integer constant suffix

["Kaveh R. Ghazi" <ghazi at caip dot rutgers dot edu>]

 > From: Zack Weinberg <zack@wolery.cumb.org>
 > 
 > __extension__ isn't appropriate and would require modifying the system
 > headers.

I agree __extension__ isn't appropriate, but for a different reason.
It elides *pedantic* warnings not the regular kind.  I was kicking
around the idea of adding a __nowarn__ keyword which would do the
analogous thing for regular warnings.  Or __nowarn__ (<parameter>) so
one could elide specific types, e.g. __traditional__,
__sign_compare__, etc.

I disagree it would require modifying system headers.  I.e. you
wouldn't stick __extension__ (or __nowarn__) into the limits.h
definition of UINT_MAX.  Instead, you would add the keyword at the
point of usage in your own code, if it triggered a harmless warning.



 > In theory, you could preserve information about where each macro
 > definition came from.  For all macros defined in system headers,
 > toggle system-header-ness on and off when you step in and out of the
 > expansion.  This may be possible right now for warnings generated by
 > the preprocessor.  The compiler doesn't have access to that level of
 > detail - the integrated preprocessor mode *could* do it, but you'd
 > have to augment the interface.  All in all, more work than I have time
 > for right now.
 > zw

How hard would it be just to do the standalone preprocessor part for
warnings generated by cpp?  We could leave the integreated
preprocessor mode for later.

		--Kaveh
--
Kaveh R. Ghazi			Engagement Manager / Project Services
ghazi@caip.rutgers.edu		Qwest Internet Solutions