[Boost-bugs] [Boost C++ Libraries] #5491: invalid result for user defined type

Subject: [Boost-bugs] [Boost C++ Libraries] #5491: invalid result for user defined type
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-04-20 02:25:10

#5491: invalid result for user defined type
-------------------------------------------------------+--------------------
 Reporter:  Akira Takahashi <faithandbrave@…>          |       Owner:  eric_niebler
     Type:  Bugs                                       |      Status:  new         
Milestone:  To Be Determined                           |   Component:  accumulator 
  Version:  Boost 1.46.1                               |    Severity:  Problem     
 Keywords:                                             |  
-------------------------------------------------------+--------------------
 `min` is invalid result for user defined type.
 {{{
 #include <iostream>
 #include <limits>
 #include <boost/accumulators/accumulators.hpp>
 #include <boost/accumulators/statistics.hpp>

 using namespace boost::accumulators;


 struct integer {
     int x;
     integer() : x(0) {}
     integer(int x) : x(x) {}

     integer& operator+=(integer other)
     {
         std::cout << "+=,";
         x += other.x;
         return *this;
     }
 };
 /*
 namespace std {
     template <>
     struct numeric_limits<integer> {
         static const bool is_specialized = true;
         static ::integer max() { return std::numeric_limits<int>::max(); }
     };
 }
 */
 bool operator<(integer a, integer b)
 {
     std::cout << "<,";
     return a.x < b.x;
 }

 int main()
 {
     accumulator_set<integer, stats<tag::min, tag::sum> > acc;

     std::cout << "add:" << std::endl;
     acc(1);
     acc(2);
     acc(3);

     std::cout << std::endl;
     std::cout << "extract:" << std::endl;
     const integer a = extract::min(acc);
     const integer b = extract::sum(acc);

     std::cout << std::endl;
     std::cout << "result:" << std::endl;
     std::cout << a.x << std::endl;
     std::cout << b.x << std::endl;
 }
 }}}
 result:
 {{{
 add:
 <,+=,<,+=,<,+=,
 extract:

 result:
 0
 6

 }}}
 `min` result should be 1.

 This problem is integer type non specialize std::numeric_limits.
 Should check std::numeric_limits::is_specialized.


 I send patch.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5491>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.