Messages in this thread | | | Subject | Re: [tip:core/urgent] WARN_ON_SMP(): Allow use in if() statements on UP | From | Steven Rostedt <> | Date | Fri, 25 Mar 2011 14:16:21 -0400 |
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On Fri, 2011-03-25 at 09:45 -0700, Linus Torvalds wrote: > On Fri, Mar 25, 2011 at 3:48 AM, tip-bot for Steven Rostedt > <srostedt@redhat.com> wrote: > > -# define WARN_ON_SMP(x) do { } while (0) > > +# define WARN_ON_SMP(x) ({0;}) > > That's a VERY odd way of writing "0". > > Am I missing something subtle?
I thought about using "0", but when WARN_ON_SMP() is used outside of an if statement, it turns into:
0;
Which seems strange to me. Thus the ({0;}) was basically a way to state that this is also a function and not just a 0 value.
Also, a quick test shows that
0;
gives the warning:
"warning: statement with no effect"
-- Steve
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