Re: [boost] More type_traits confusion

From: Howard Hinnant (hinnant_at_[hidden])
Date: 2001-01-21 23:03:23

is_standard_signed_integral<char>::value returns false everywhere (by 
design).  If char is a signed quantity on the compilers you are testing, 
then this is to be expected.

-Howard

David Abrahams wrote on 1/21/2001 11:04 PM
>On /every/ compiler I can test, the following fails:
>
>
>    BOOST_STATIC_ASSERT(boost::is_signed_integral<char>::value ==
>boost::detail::is_signed<char>::value);
>
>With the following definition:
>
>namespace boost { namespace detail {
>
>  template <class Number>
>  struct is_signed
>  {
>      enum { value = (Number(-1) < Number(0)) };
>  };
>}}
>
>Something wacky is going on here.
>
>-Dave
>
>----- Original Message -----
>From: "Howard Hinnant" <hinnant_at_[hidden]>
>To: <boost_at_[hidden]>
>Sent: Sunday, January 21, 2001 9:19 PM
>Subject: Re: [boost] More type_traits confusion
>
>
>> David Abrahams wrote on 1/21/2001 9:13 PM
>> >> Note that is_signed<char>::value is both well formed and well-defined,
>> >> though its result will vary with implementations.
>> >
>> >I think you should look again. For CW and GCC, is_signed<char>::value
>> >reports false, even though chars are signed.
>>
>> I can't speak for gcc, but I'm not duplicating your results for cw.  My
>> tests are showing that cw reports true for is_signed<char>::value unless
>> "Use Unsigned Chars" is checked in the language prefs panel, in which
>> case it reports false (both PPC and Windows).
>>
>> -Howard
>>
>>
>>
>
>
>
>