Topic: Where in the C++11 standard does it specify when a constexpr function can be evaluated during translation?
Author: s.scott.schurr@googlemail.com
Date: Tue, 18 Dec 2012 16:06:15 CST
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On Saturday, December 15, 2012 10:54:25 AM UTC-8, Daniel Kr gler wrote:
> Am 14.12.2012 18:15, schrieb sschurr:
> > The heart of the question is this:
> >
> > <quote>
> >
> > I've been looking through the C++11 FDIS (N3242, available
> > at http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/)
> > to try and determine two things:
> >
> > o When is the compiler obligated to evaluate a constexpr
> > function during translation?
> >
> > o When is the compiler allowed to evaluate a constexpr
> > function during translation?
> >
> > [...snip...]
>
> Answers to these questions are related to the context, in which a
> constexpr function is used. I would like to warn you that the standard
> itself is not a document that is written to answer such questions
> directly. If you want to enumerate these cases, you have to read through
> all the standard and have to find those places that impose such a
> requirement. This is extremely hard work and I'm not willing to do that
> at the moment ;-) But if you are willing to accept some general
> conclusions this can lead to still useful rules of the thumb.
[snip a lot of very useful information]
Wow. I'd like to express my thanks to Mr. Kr gler for his extremely detailed and useful response. I know that well thought out answers, like Mr. Kr gler's, take a lot of time to compose. It's great to have someone from inside the C++ standards community take the time to help innocents (like me) come up to speed.
Please accept my thanks and gratitude.
SSchurr
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