Re: [Qemu-devel] [PATCH v2 13/18] nvdimm: build namespace config data

[Xiao Guangrong]

On 08/28/2015 07:59 PM, Stefan Hajnoczi wrote:
> On Wed, Aug 26, 2015 at 06:42:01PM +0800, Xiao Guangrong wrote:
> > On 08/26/2015 12:16 AM, Stefan Hajnoczi wrote:
> > > On Fri, Aug 14, 2015 at 10:52:06PM +0800, Xiao Guangrong wrote:
> > > > +#ifdef NVDIMM_DEBUG
> > > > +#define nvdebug(fmt, ...) fprintf(stderr, "nvdimm: " fmt, ## __VA_ARGS__)
> > > > +#else
> > > > +#define nvdebug(...)
> > > > +#endif
> > >
> > > The following allows the compiler to check format strings and syntax
> > > check the argument expressions:
> > >
> > > #define NVDIMM_DEBUG 0  /* set to 1 for debug output */
> > > #define nvdebug(fmt, ...) \
> > >      if (NVDIMM_DEBUG) { \
> > >          fprintf(stderr, "nvdimm: " fmt, ## __VA_ARGS__); \
> > >      }
> > >
> > > This approach avoids bitrot (e.g. debug format string arguments have
> > > become outdated).
> >
> > Really good tips, thanks for your sharing.
>
> I forgot the do { ... } while (0) in the macro to make nvdebug("hello
> world"); work like a normal C statement.

Got it, will keep it in my mind.