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From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
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Date: Mon, 31 Aug 2015 14:25:21 +0800
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Subject: Re: [Qemu-devel] [PATCH v2 13/18] nvdimm: build namespace config
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To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org, Stefan Hajnoczi <stefanha@gmail.com>, mtosatti@redhat.com, qemu-devel@nongnu.org, pbonzini@redhat.com, imammedo@redhat.com, rth@twiddle.net



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 become outdated).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.