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

[Stefan Hajnoczi]

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become outdated).