Re: [Qemu-devel] [RFC PATCH v3 02/11] Fix errors and warnings while compiling with c++ compilier

[Stefan Hajnoczi]

On Thu, May 23, 2013 at 06:34:43PM +0000, Tomoki Sekiyama wrote:
> On 5/23/13 8:12 , "Stefan Hajnoczi" <address@hidden> wrote:
> 
> >On Tue, May 21, 2013 at 11:33:41AM -0400, Tomoki Sekiyama wrote:
> >> Add C++ keywords to avoid errors in compiling with c++ compiler.
> >> This also renames class member of PciDeviceInfo to q_class.
> >> 
> >> Signed-off-by: Tomoki Sekiyama <address@hidden>
> >> ---
> >>  hmp.c           |    2 +-
> >>  hw/pci/pci.c    |    2 +-
> >>  scripts/qapi.py |    9 ++++++++-
> >>  3 files changed, 10 insertions(+), 3 deletions(-)
> >
> >Please also extend scripts/checkpatch.pl.  Otherwise it is very likely
> >that C++ keywords will be introduced again in the future.  Most people
> >will not build the VSS code and therefore checkpatch.pl needs to ensure
> >that patches with C++ keywords will not be accepted.
> >
> >Stefan
> 
> I think it would be difficult to identify problematic C++ keywords usage
> from patches because headers can legally contain C++ keywords and
> checkpatch.pl doesn't know where it should be used.
> Do you have any good ideas?

We can ignore false warnings for 0.1% of patches (the ones that touch
VSS C++ code).  But for the remaining 99.9% of patches it's worth
guarding against VSS bitrot.

Remember not many people will compile it and therefore they won't notice
when they break it.  I really think it's worth putting some effort in
now so VSS doesn't periodically break.

checkpatch.pl is a hacky sort of C parser.  It already checks for a
bunch of similar things and it knows about comments, macros, and
strings.  It does not perform #include expansion, so there is no risk of
including system headers that have C++ code.

Stefan