Re: do { } while (0) question

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Peter Zijlstra wrote:
On Tue, 2006-08-01 at 02:03 -0700, Hua Zhong wrote:
#if KILLER == 1
#define MACRO
#else
#define MACRO do { } while (0)
#endif

{
	if (some_condition)
		MACRO

	if_this_is_not_called_you_loose_your_data();
}

How do you want to define KILLER, 0 or 1? I personally choose 0.
Really? Does it compile?

No, and that is the whole point.

The empty 'do {} while (0)' makes the missing semicolon a syntax error.

Bulls^WNope, it was a bad example (we don't want to break the compilation, just not want to emit a warn or an err).

I can't emit an error with the thing like that, only a warning, but we are not using -Werror to get err from a warn. Thing such this would emit empty-statement warn if define KILLER as 1:
#if KILLER == 1
#define MACRO
#else
#define MACRO do { } while (0)
#endif

{
 	if (some_condition)
 		MACRO;
	else
		do_something();
}

regards,
--
<a href="http://www.fi.muni.cz/~xslaby/";>Jiri Slaby</a>
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8  22A0 32CC 55C3 39D4 7A7E
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux