[Boost-bugs] [Boost C++ Libraries] #12081: the minmax creates dangling references too easily

Subject: [Boost-bugs] [Boost C++ Libraries] #12081: the minmax creates dangling references too easily
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-03-20 20:23:47

#12081: the minmax creates dangling references too easily
------------------------------+----------------------
 Reporter:  anonymous         |      Owner:  marshall
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  minmax
  Version:  Boost 1.60.0      |   Severity:  Problem
 Keywords:                    |
------------------------------+----------------------
 First.
 minmax's example codes has created dangling references.

 {{{
 boost::tuple<int const&, int const&> result1 = boost::minmax(1, 0);
 //actual code
 boost::tuple<int, int> result1 = boost::minmax(1, 0); //expected code
 }}}

 http://www.boost.org/doc/libs/1_60_0/libs/algorithm/minmax/index.html

 [[BR]]
 http://www.boost.org/doc/libs/1_60_0/libs/algorithm/minmax/example/minmax_ex.cpp


 [[BR]]

 Second.
 The design of minmax is unsuitable for that of C++11 era.
 Consider the following.

 {{{
 auto tp = minmax(1,2);
 tp.get<0>(); // Undefined behavior
 }}}
 This code looks like fairy normal, but it causes undefined behavior. Since
 the minmax returns tuple<T const&, T const&>, the 'auto tp' has dangling
 references. [[BR]]

 I think we should change the return type from tuple<T const&, T const&> to
 tuple<T,T>.

 See also: https://groups.google.com/a/isocpp.org/forum/#!topic/std-

 discussion/HLiJJBRNYSw

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12081>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.