Re: [boost] [qvm] deduce_xx traits wouldn't introduce ODR issues.

Subject: Re: [boost] [qvm] deduce_xx traits wouldn't introduce ODR issues.
From: Sergey Mitsyn (svm_at_[hidden])
Date: 2015-12-31 04:24:24

On 31.12.2015 12:00, Rob Stewart wrote:
> On December 31, 2015 2:42:55 AM EST, Sergey Mitsyn <svm_at_[hidden]>
> wrote:
>>
>> Correct me if I'm wrong, but it to me seems that the root of evil
>> here is a specialization by third party library, by which I mean
>> the case when template from library X is specialized with type(s)
>> exclusively from library (libraries) Y (Y might be the same as X)
>> by library Z (which is neither X nor Y, third party). If it's true,
>> an ODR would be caused for a user even if _unary_ deduce_m (or any
>> other deduce_X) will be specialized by two unrelated third party
>> libraries A and B imported by user.
>
> Your point is valid except that one-type customization points are
> likely to be provided by the library providing the type X or Y, or by
> the library providing the customization point using a separate header
> (opt in).

But then until they don't it's still an issue, because eventually they 
may provide, so a specialization made by a library user is a ticking bomb.

>
> Bold warnings in the documentation may be the only real solution to
> the issue.
>
> ___ Rob
>
> (Sent from my portable computation engine)
>
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