Re: [Boost-bugs] [Boost C++ Libraries] #12720: Implement is_floating_point and is_arithmetic for float128

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #12720: Implement is_floating_point and is_arithmetic for float128
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2017-01-02 16:54:33

#12720: Implement is_floating_point and is_arithmetic for float128
-----------------------------------------+----------------------------
  Reporter:  Charles Karney <charles@…>  |      Owner:  johnmaddock
      Type:  Feature Requests            |     Status:  closed
 Milestone:  To Be Determined            |  Component:  multiprecision
   Version:  Boost 1.60.0                |   Severity:  Problem
Resolution:  wontfix                     |   Keywords:
-----------------------------------------+----------------------------
Changes (by johnmaddock):

 * status:  new => closed
 * resolution:   => wontfix

Comment:

 Sorry, no can do: type_traits work on the what kind of type an object is,
 not how they behave.  float128 is a '''class type''' (and responds true to
 {{{is_class}}}), it genuinely should not respond true to
 {{{is_arithmetic}}} etc.

 You code above should work fine if you use boost::mt19937 etc rather than
 the std versions.

 It's probably worth while filing a gcc/libstdc++ bug report as well since
 the assert they are using could be replaced by one that uses
 numeric_limits<> to verify a type behaves as a floating point type - and
 numeric_limits is one trait we are allowed to specialize (and do so).

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12720#comment:1>
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