Re: [PATCH] Do not expand macros to 'defined'

[Simon Marchi <simon dot marchi at polymtl dot ca>]

On 2019-01-16 15:48, Andreas Schwab wrote:
> On Jan 16 2019, Simon Marchi <simon.marchi@polymtl.ca> wrote:
>
> > The patch LGTM, I agree these macros are not really needed.  But I am
> > confused, does this actually fix your c++ build?  You mentioned you 
> > were
> > using g++ (and therefore cpp), which supposedly can handle this fine:
> >
> > https://gcc.gnu.org/onlinedocs/cpp/Defined.html
> >
> > If so, what did the error look like?
>
> This has nothing to do with C vs. C++, both have the same wording:
>
>     If the token defined is generated as a result of this replacement
>     process or use of the defined unary operator does not match one of
>     the two specified forms prior to macro replacement, the behavior is
>     undefined.
>
> Andreas.

That's why I was confused, the purpose of Pavel's patch that was 
replaced by this one is C++-oriented:

https://sourceware.org/ml/gdb-patches/2019-01/msg00241.html

So in the end it looks like the issue is indeed not about C++, but about 
his usage of -Wextra (-Wexpansion-to-defined).

Simon