-Wold-style-cast and standard library macros

[Yang Zhang]

John (Eljay) Love-Jensen wrote:
> Hi Yang Zhang,
> 
>> But is there any workaround for this problem in general, where the source of
> the problem is a macro defined in a system header?  I'm seeing the same problem
> with FD_SET, FD_ISSET, etc.
> 
> Well... I did provide a general workaround.

What I really intended to ask: is there any hope of seeing GCC not issue 
warnings for expansions of macros that were defined in a C standard 
library, such that users don't need to read through and re-define these 
C standard library macros?  I understand what's going on and I 
understand your suggested workaround.  Indeed it may be the only 
workaround for now, but I hope you'll agree that it's less than ideal. 
Realization of this seems slightly tricky since there is no 1:1 mapping 
between line numbers and macro expansions, so the preprocessor can't 
help pinpoint original location of the macro definition.  Perhaps having 
the preprocessor emit some sort of *in-line* source line number 
annotation would be the simplest approach to enable the compiler to 
ignore these:

   __line__("<original header file>", <line no>, <expanded macro>)

> 
> Another solution presented by someone on this forum many years ago is to use
> a tool like Perl (Python, Ruby, or even sed) to filter the output from the
> warnings deemed benign which you don't want to see.  Perhaps this approach
> is a more suitable general workaround.

This doesn't work with -Werror.
-- 
Yang Zhang
http://www.mit.edu/~y_z/