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

From: Joe Perches
Date: Fri Jul 20 2012 - 11:49:54 EST

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)
> 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

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