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Re: static_cast and std::vector

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>>>
>>> Both the C-style cast and the static_cast are wrong; you cannot cast a
>>> std::vector<base*> to a std::vector<derived*>.
>>>
>>> Instead have these getter functions return a std::vector<base*> and
>>> downcast (using static_cast or dynamic_cast) the vector's elements
>>> instead elsewhere in your code.
>>>
>>> /Leigh
>>
>>
>> I do not see why the C-style cast is wrong. It works flawlessly across a
>> wide range of compilers and systems. I can understand the problem with
>> C++ static_cast, but I was hoping there was a way around it. If there is
>> not a valid C++ way to do this, I'll leave it as is.
>
> Just because something "works" does not means that it is "correct". The
> language allows you to perform the C style cast (or reinterpret_cast)
> however *using* the resultant object reference by invoking a std::vector
> member function results in undefined behaviour. Undefined behaviour can
> "silently work" on a particular implementation but that does not mean it
> is correct; it isn't, it is a bug. The basic reason why this is the case
> here is due to the fact that std::vector<base*> and
> std::vector<derived*> are unrelated types.
>

Ok.  Thanks for the explanation.  I may look into fixing this according 
to your suggestion.

John

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static_cast and std::vector john <gh14tq5@yahoo.com> - 2012-01-20 08:56 -0500
  Re: static_cast and std::vector Leigh Johnston <leigh@i42.co.uk> - 2012-01-20 14:00 +0000
    Re: static_cast and std::vector john <gh14tq5@yahoo.com> - 2012-01-20 09:58 -0500
      Re: static_cast and std::vector Leigh Johnston <leigh@i42.co.uk> - 2012-01-20 15:02 +0000
        Re: static_cast and std::vector john <gh14tq5@yahoo.com> - 2012-01-20 10:28 -0500
      Re: static_cast and std::vector "Fred Zwarts \(KVI\)" <F.Zwarts@KVI.nl> - 2012-01-20 16:48 +0100
        Re: static_cast and std::vector Leigh Johnston <leigh@i42.co.uk> - 2012-01-20 16:02 +0000
          Re: static_cast and std::vector Joshua Maurice <joshuamaurice@gmail.com> - 2012-01-20 14:30 -0800
      Re: static_cast and std::vector Juha Nieminen <nospam@thanks.invalid> - 2012-01-20 19:04 +0000
  Re: static_cast and std::vector Tobias Müller <troplin@bluewin.ch> - 2012-01-21 08:56 +0000
    Re: static_cast and std::vector john <gh14tq5@yahoo.com> - 2012-01-23 12:47 -0500
      Re: static_cast and std::vector Ian Collins <ian-news@hotmail.com> - 2012-01-24 09:22 +1300
  Re: static_cast and std::vector Pavel <pauldontspamtolk@removeyourself.dontspam.yahoo> - 2012-01-21 23:02 -0500

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