[Insight-users] NumericTraits level 3 warnings on VS 2008

[Niels Dekker]

Denis Shamonin wrote:
> I've compile warnings on VS 2008 (Itk 3.10.0) for
> Class:
> NumericTraits<char> : public vcl_numeric_limits<char>
>
> Function:
>  static char min() { return char(255) < 0 ? -128 : 0; }
>  static char max() { return char(255) < 0 ? 127 : 255; }
>
> Warnings:
> itk3\include\common\itkNumericTraits.h(165) : warning C4310: cast
> truncates constant value
> itk3\include\common\itkNumericTraits.h(166) : warning C4310: cast
> truncates constant value
>
> Should it be changed to
>  static char min() { const char minValue=255;
>    return char(minValue) < 0 ? -128 : 0; }
>  static char max() { const char maxValue=255;
>    return char(maxValue) < 0 ? 127 : 255; }

Denis, I agree that those warnings are annoying, but I don't really 
understand your proposed solution either, casting a char to a char. 
Also I think your approach might trigger another warning on MSVC 9 (VS 
2008), "C4309: 'initializing' : truncation of constant value".


I think it would be better to just locally disable warning C4310, in 
itkNumericTraits.h:

  #ifdef _MSC_VER
  #pragma warning (push)
  #pragma warning (disable: 4310) // cast truncates constant value
  #endif

  static char min() { return char(255) < 0 ? -128 : 0; }
  static char max() { return char(255) < 0 ? 127 : 255; }

  #ifdef _MSC_VER
  #pragma warning (pop)
  #endif

Please take a look at the attached patch.  Is it okay if I commit it to 
Insight/Code/Common?


Kind regards,
--
Niels Dekker
http://www.xs4all.nl/~nd/dekkerware
Scientific programmer at LKEB, Leiden University Medical Center 
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