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Re: [C] Fix PR57258: unused variable warning is emitted for volatile variables


On Fri, Nov 8, 2013 at 5:03 PM, Mike Stump <mikestump@comcast.net> wrote:
> On Nov 7, 2013, at 5:13 PM, Mingjie Xing <mingjie.xing@gmail.com> wrote:
>> Well, it is my understanding that the warning should be emitted for a
>> volatile variable only if it is not accessed.  Initialization means
>> accessing, even though it is not used anywhere.
>
> Let me try.  A warning is useful, if there is no way a conforming program can tell that the variable exists or not.  So, the question is, how can you notice the variable?  Answer, there is no way, so, there is no utility in having the variable.  The warning is to tell the user to remove the dead variable.

I am sort of lost.  The bug is straightforward and it suggests the
volatile variable is actually used if it is declared with an
initialization, and GCC should not emit warning message for it.

The patch is fixing this, right?  Any explanation?

Thanks,
bin

-- 
Best Regards.


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