Re: incorrect use of 'pure' attribute

Paul Eggert <[email protected]> writes:

> On 8/8/26 05:38, Sam James wrote:
>> The comment simply isn't right and it makes an assertion that doesn't
>> reflect reality. It is not validly const if it uses global memory to
>> affect what it returns, even if later calls are OK.
>
> But __eloop_threshold doesn't use global memory to affect what it
> returns. It always returns the same value, every time. So, even though
> __eloop_threshold uses static storage (I assume that's what you mean
> by "global memory"), its use of that static storage doesn't affect
> what it returns.

Yes, you're right. My apologies! I'd missed it's static apparently.

>
> In this sense I guess __eloop_threshold differs from a common C++
> idiom, in which even though the function always returns the same
> value, that value is affected by what's already in
> memory. __eloop_threshold does not have that property.
>
> If my understanding is incorrect I'd appreciate a clarification, e.g.,
> an example of an optimization that GCC might apply that would be
> invalid for __eloop_threshold.

sam

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