[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-block] [Qemu-devel] [PATCH] block: always compile-check debug
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH] block: always compile-check debug prints |
Date: |
Thu, 28 Apr 2016 10:16:39 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
adding qemu-block
On 04/28/2016 02:01 AM, Zhou Jie wrote:
> Files with conditional debug statements should ensure that the printf is
> always compiled.
> This prevents bitrot of the format string of the debug statement.
>
> Signed-off-by: Zhou Jie <address@hidden>
> ---
> +++ b/block/curl.c
> @@ -32,14 +32,15 @@
> #include <curl/curl.h>
> #include "qemu/cutils.h"
>
> -// #define DEBUG_CURL
> +#define DEBUG_CURL 0
Other patches doing similar work keep the user-visible witness as
defined/undefined, so that you can add -DDEBUG_CURL to the CFLAGS
without editing any .c files, and create a secondary witness as the
actual conditional. See 8c6597123af for an example, where I did:
#ifdef DEBUG_NBD
-#define TRACE(msg, ...) do { \
- LOG(msg, ## __VA_ARGS__); \
-} while(0)
+#define DEBUG_NBD_PRINT 1
#else
-#define TRACE(msg, ...) \
- do { } while (0)
+#define DEBUG_NBD_PRINT 0
#endif
+#define TRACE(msg, ...) do { \
+ if (DEBUG_NBD_PRINT) { \
The way you did it, I cannot add -DDEBUG_CURL (because you blindly
redefine it back to 0), but have to edit the .c file.
> // #define DEBUG_VERBOSE
>
> -#ifdef DEBUG_CURL
> -#define DPRINTF(fmt, ...) do { printf(fmt, ## __VA_ARGS__); } while (0)
As long as we're touching this, should we make this print to stderr
instead of stdout?
> +++ b/block/sheepdog.c
> @@ -293,14 +293,13 @@ static inline size_t count_data_objs(const struct
> SheepdogInode *inode)
> }
>
> #undef DPRINTF
> -#ifdef DEBUG_SDOG
> -#define DPRINTF(fmt, args...) \
> - do { \
> - fprintf(stdout, "%s %d: " fmt, __func__, __LINE__, ##args); \
Again, as long as we're touching this, 'fprintf(stdout,' looks stupid.
Either make it 'printf(' or make the debug go to stderr.
> +#define DEBUG_SDOG 0
Same comment about letting the mere definition of the witness variable
be sufficient
Thanks for doing this; looking forward to v2 (and/or comments from
someone more familiar with whether the block layer should be sending
debug comments to stderr instead of stdout)
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: [Qemu-block] [Qemu-devel] [PATCH] block: always compile-check debug prints,
Eric Blake <=