Re: [PATCH] checkpatch: Add checks for do {} while (0) macro misuses

[Joe Perches <joe@perches.com>]

On Fri, 2012-07-20 at 14:40 +0000, Betty Dall wrote:

> I reviewed this and tested it out on the qib.h file we were looking at yesterday 
> and it worked well. I was worried about a nested do {} while(0), because it will 
> match with the first while. Here is a test case:
> #define qib_devinfo(pcidev, fmt, ...) \
>         do { \
>                 do { \
>                         dev_info(&(pcidev)->dev, fmt, ##__VA_ARGS__); \
>                 } while (0); \
>         } while (0)
> 
> Checkpatch.pl didn't complain about that one. Granted, it is a contrived test 
> case. Your change will catch the real problems.

Hi Betty.

Wow, you're thorough.  Thanks for testing.

I don't mind that it doesn't work in all cases.
I suppose this would fail for loops too.

checkpatch is a pretty limited tool as it depends on
the code being compilable and doesn't really understand
c syntax.  It is just a convenience tool and lots of
its logic is incomplete and some of its output can be
happily ignored.

cheers, Joe