[Boost-bugs] [Boost C++ Libraries] #2428: [random] missing member initialization of generator_iterator ctor

Subject: [Boost-bugs] [Boost C++ Libraries] #2428: [random] missing member initialization of generator_iterator ctor
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2008-10-22 11:18:49

#2428: [random] missing member initialization of generator_iterator ctor
----------------------------------------------------+-----------------------
 Reporter:  Johannes Brunen <JBrunen_at_[hidden]>  |       Owner:  no-maintainer
     Type:  Bugs                                    |      Status:  new          
Milestone:  Boost 1.37.0                            |   Component:  random       
  Version:  Boost 1.36.0                            |    Severity:  Problem      
 Keywords:  generator_iterator default ctor         |  
----------------------------------------------------+-----------------------
 I am trying to use boost::generator_iterator with a random number
 generator as follows:

 ---
 #include <boost/generator_iterator.hpp>
 #include <boost/random/mersenne_twister.hpp>

 class my_generator {...};

 my_generator gen;

 boost::generator_iterator<my_generator> first(&gen);
 boost::generator_iterator<my_generator> last;

 boost::random::mt19937 rng; rng.seed(first, last);

 ---

 Sadly the default constructor of generator_iterator leaves m_gen
 uninitialized and the seed function is trying to compare first
 with last.

 This yield undefined behavior.

 Solution: default ctor member initialization:

 generator_iterator.hpp : line 38

 generator_iterator() : m_g(0), m_value(0) {}

-- 
Ticket URL: <http://svn.boost.org/trac/boost/ticket/2428>
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