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

2015-08-31 Thread 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become outdated).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.
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Re: [Qemu-devel] [PATCH v2 13/18] nvdimm: build namespace config data

2015-08-28 Thread Stefan Hajnoczi
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 become outdated).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.
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Re: [Qemu-devel] [PATCH v2 13/18] nvdimm: build namespace config data

2015-08-26 Thread Xiao Guangrong



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

2015-08-25 Thread 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).
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