[Boost-bugs] [Boost C++ Libraries] #4139: gcd_integer in common_factor_rt.hpp fails to compile for some IntegerTypes (like mpz_class)

Subject: [Boost-bugs] [Boost C++ Libraries] #4139: gcd_integer in common_factor_rt.hpp fails to compile for some IntegerTypes (like mpz_class)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-04-22 14:58:08

#4139: gcd_integer in common_factor_rt.hpp fails to compile for some IntegerTypes
(like mpz_class)
-------------------------------------+--------------------------------------
 Reporter:  mitchnull@…              |       Owner:  johnmaddock
     Type:  Bugs                     |      Status:  new        
Milestone:  To Be Determined         |   Component:  math       
  Version:  Boost Development Trunk  |    Severity:  Problem    
 Keywords:  gcd_integer              |  
-------------------------------------+--------------------------------------
 The use of the ternary operator in gcd_integer in common_factor_rt.hpp:119
 can lead to compile time error if the unary operator- of the given type
 doesn't return the same type as itself:

 return ( result < zero ) ? -result : result;

 as the type of "-result" and "result" differs.

 Either a static_cast is needed like:

 return ( result < zero ) ? static_cast<IntegerType>(-result) : result;

 or the one-liner should be replaced with an if like this:

         if ( result < zero )
         {
             return -result;
         }
         else
         {
             return result;
         }

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4139>
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