Re: [Boost-users] [integer_traits problem

Robert Ramey wrote:

I'm having problems with integer traits when passed an __int64 type data type under Visual C++.

I run the following test:

boost::mpl::print< boost::mpl::integral_c< boost::intmax_t, boost::integer_traitsboost::intmax_t::const_min

...

x13;

boost::mpl::print< boost::mpl::integral_c< boost::intmax_t, boost::integer_traitsboost::intmax_t::const_max

...

x8;

What I expect to get for const_min is: ... 1> T=boost::mpl::integral_cboost::intmax_t,0x8000000000000000 ...

What I get is:

...

see reference to class template instantiation 'boost::mpl::print<T>' being compiled 1> with 1> [ 1> T=boost::mpl::integral_cboost::intmax_t,0x800000000 1> ] 1>c:\boostrelease\boost\mpl\print.hpp(51) : warning C4308: negative integral constant converted to unsigned type 1> c:\projects\boost

1>test_fixed_type.cpp 1>c:\boostrelease\boost\mpl\print.hpp(51) : warning C4308: negative integral constant converted to unsigned type 1> c:\projects\boost projects\safe_numerics\include\test_fixed_type.cpp(13) projects\safe_numerics\include\test_fixed_type.cpp(20)

...

see reference to class template instantiation 'boost::mpl::print<T>' being compiled 1> with 1> [ 1> T=boost::mpl::integral_cboost::intmax_t,0x7fffffffffffffff 1> ]

That is the value for const_min is not correct !!. Note I've tried various different types such as using __int64 and also changed the rendering of he real vale to _I64_MIN. None of this seems to fix things. I've also tried making my own specialzation of integral_c for this type: template struct integral_c { BOOST_STATIC_CONSTANT(boost::intmax_t, value = C); typedef integral_c_tag tag; typedef integral_c type; typedef boost::intmax_t value_type; operator boost::intmax_t() const { return this->value; } };

Hmmm now I'm wondering about BOOST_STATIC_CONSTANT. and looking at the documenation of BOOST_STATIC_CONSTANT shows it's not really expected to work on anything wider than an int.

What should one do in a case like this?

I just changed the specialization above to: template struct integral_c { //BOOST_STATIC_CONSTANT(boost::intmax_t, value = C); static const boost::intmax_t value = C; typedef integral_c_tag tag; typedef integral_c type; typedef boost::intmax_t value_type; operator boost::intmax_t() const { return this->value; } }; and it didn't make any difference so I"m really stumped

Robert Ramey