Re: [boost] [config][mpl][type_traits][integer] BOOST_STATIC_CONSTANT should use constexpr

Subject: Re: [boost] [config][mpl][type_traits][integer] BOOST_STATIC_CONSTANT should use constexpr
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2013-04-20 05:45:59

Le 20/04/13 11:15, Antony Polukhin a écrit :
> 2013/4/20 Vicente J. Botet Escriba <vicente.botet_at_[hidden]>:
>> Would it be preferable to add BOOST_STATIC_CONSTANT_11 and change every use
>> of BOOST_STATIC_CONSTANT by BOOST_STATIC_CONSTANT_11 and deprecate
>> BOOST_STATIC_CONSTANT?
> I would rather change the definitioon of BOOST_STATIC_CONSTANT to
>
> #  ifdef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
> #       define BOOST_STATIC_CONSTANT(type, assignment) enum { assignment }
> #  else
> #     define BOOST_STATIC_CONSTANT(type, assignment) static
> *BOOST_CONSTEXPR_OR_CONST* type assignment
> #  endif
>
> Code from example:
>
> template <typename T>
> const bool trait::value;
>
> newer was correct, because compilers with
> BOOST_NO_INCLASS_MEMBER_INITIALIZATION define it to enum. So proposed
> change shall not break correct code.
>
>
Humm,

I had made the change in BOOST_STATIC_CONSTANT and I'm getting error for 
example in

namespace boost {
namespace type_traits {

template <int b1, int b2>
struct ice_eq
{
BOOST_STATIC_CONSTANT(bool, value = (b1 == b2));
};

template <int b1, int b2>
struct ice_ne
{
BOOST_STATIC_CONSTANT(bool, value = (b1 != b2));
};

#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
template <int b1, int b2> bool const ice_eq<b1,b2>::value; // *********
template <int b1, int b2> bool const ice_ne<b1,b2>::value; // *********
#endif

for which I have needed to change const by BOOST_CONSTEXPR_OR_CONST.

darwin.compile.c++ 
../../../bin.v2/libs/config/test/math_info.test/darwin-4.8.0x/debug/math_info.o
In file included from ../../../boost/type_traits/ice.hpp:18:0,
from ../../../boost/type_traits/is_reference.hpp:18,
from ../../../boost/type_traits/intrinsics.hpp:206,
from ../../../boost/type_traits/alignment_of.hpp:15,
from math_info.cpp:24:
../../../boost/type_traits/detail/ice_eq.hpp:29:53: erreur: 
redeclaration ‘boost::type_traits::ice_eq<b1, b2>::value’ differs in 
‘constexpr’
template <int b1, int b2> bool const ice_eq<b1,b2>::value;
^

What am I missing?

Best,
Vicente