how to deal with variable set but not used warnings?

[Matthew Macy]

On Sun, Jun 3, 2018 at 2:40 PM, Theron <theron.tarigo at gmail.com> wrote:
>> 4. Disable the stupid warning in the Makefile / build system. If you don't
>> care, and there's a good reason for what you are doing (sounds like there
>> is), better to just disable the warning as so much useless noise.
>>
>> Warner
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>
> Or possibly, alongside a comment as in (3), use one of these:
> 5 - Disable warning pragma -
> http://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html
> 6 - Use __attribute__((unused)) -
> https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#Common-Variable-Attributes


There is already an __unused alias for #6. It's what I've used to
annotate variables that are only used by INVARIANTS builds. It
legitimately finds a bunch of dead code. However, 90+% of the
instances of the warning are not interesting.
-M