[cfe-commits] [Patch][Review] constexpr-ification of <limits> and random number generators

[Howard Hinnant]

On Apr 2, 2012, at 2:44 AM, Jonathan Sauer wrote:

> Hello,
> 
>> [...]
>> That's a good argument, thanks.  I guess I'm now favoring Richard's exact proposal:
>> 
>> #ifndef _LIBCPP_HAS_NO_CONSTEXPR
>> #define _LIBCPP_CONSTEXPR constexpr
>> #else
>> #define _LIBCPP_CONSTEXPR
>> #endif
>> 
>> Then use
>> 
>> _LIBCPP_CONSTEXPR const int n = 5;
>> 
>> for variables, and
>> 
>> struct S {
>> _LIBCPP_CONSTEXPR S();
>> _LIBCPP_CONSTEXPR int f() const;
>> };
>> 
>> for functions.
>> 
>> I like it better than Jonathan's, and my first _CONSTEXPR_1, _CONSTEXPR_0 because of the single macro that is either going to be constexpr or not.  The source code won't be as compact, but I find it more readable (though just a little too verbose).
>> 
>> Jonathan, I really appreciate you're work in <limits> and <random> and sorry about thrashing you around on this issue.  But I felt it important to hammer this out before we get too invested in the wrong strategy, as we already are with my ill-fated:
> 
> Oh, no problem: First of all adapting my patch took me about 10 minutes, and second of all I did it on a whim,
> so any unnecessary work done by me is my own fault :-)
> 
> I prepared a new patch using _LIBCPP_CONSTEXPR and have it attached. Please review and, if ok, commit.

Thanks.  Two problems:

1.  Please include a patch to CREDITS.TXT

2.  Please test /test/numerics/rand and test/language.support/support.limits with constexpr turned off (say in C++03 mode).  I'm getting many failures under rand.

Howard