Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.std.c++ > #471

Re: Re: Request för std::vector and possibly others: minimal initalization

Show all headers | View raw

In article<b94ffa35-1289-4a00-b9fd-92a56dfee459@w32g2000vbt.googlegroups.com>,
henrikv<henrik.vallgren@stream-space.com>  wrote:
>struct NoInitDummy
>{
>    NoInitDummy() {}
>
>    // Make this behave like a Dummy using conversion operators etc
>    int a;
>};

C++ gives some rules about when things get initialized, which usually
helps you, but sometimes just gets in your way.  So then you think, 'you
want the one function to run but not the other one?' and then you're
like 'umm, -yeah-, that's what i want'.  So then you think, 'is my
design defective?', or is this a case where C++ has inferred what
behavior you want, when actually that is not the behavior you want.

An example is class Y derives from class X.  The way to initialize Y, so
we are told, is to call a function to initialize it so far as being an X
object, then call another function to convert an X object to a Y object.
Sometimes this is awkward.  Sometimes the easiest thing to do is to say
'the Y initializer will do everything, and please don't talk to the X
initializer at all'.  I don't think that is bad design, it's just where
some of the tacit assumptions in the language go a bit awkward; it's not
saying you *can't* do that, that's what an 'uninit' class is there for.


-- 
[ comp.std.c++ is moderated.  To submit articles, try posting with your ]
[ newsreader.  If that fails, use mailto:std-cpp-submit@vandevoorde.com ]
[              --- Please see the FAQ before posting. ---               ]
[ FAQ: http://www.comeaucomputing.com/csc/faq.html                      ]

Back to comp.std.c++ | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Request för std::vector and possibly others: minimal initalization henrikv <henrik.vallgren@stream-space.com> - 2012-03-19 23:35 -0700
  Re: Request för std::vector and possibly others: minimal initalization Francis Glassborow<francis.glassborow@btinternet.com> - 2012-03-21 11:35 -0700
    Re: Request för std::vector and possibly others: minimal initalization henrikv<henrik.vallgren@stream-space.com> - 2012-03-23 17:09 -0700
      Re: Request för std::vector and possibly others: minimal initalization Daniel Krügler <daniel.kruegler@googlemail.com> - 2012-03-24 19:25 -0700
      Re: Request för std::vector and possibly others: minimal initalization Francis Glassborow <francis.glassborow@btinternet.com> - 2012-03-24 19:28 -0700
  Re: Request för std::vector and possibly others: minimal initalization Jason McKesson<jmckesson@gmail.com> - 2012-03-21 11:35 -0700
    Re: Request för std::vector and possibly others: minimal initalization henrikv<henrik.vallgren@stream-space.com> - 2012-03-23 17:10 -0700
      Re: Request för std::vector and possibly others: minimal initalization Jason McKesson<jmckesson@gmail.com> - 2012-03-24 17:55 -0700
      Re: Request for std::vector and possibly others: mi brangdon@cix.compulink.co.uk (Dave Harris) - 2012-03-24 19:24 -0700
      Re: Re: Request för std::vector and possibly others: minimal initalization jgk@panix.com (Joe keane) - 2012-03-27 12:10 -0700
    Re: Request för std::vector and possibly others: minimal initalization Kevin McCarty<kmccarty@gmail.com> - 2012-03-23 17:11 -0700
      Re: Request för std::vector and possibly others:   minimal initalization Miles Bader<miles@gnu.org> - 2012-03-24 17:55 -0700
        Re: Request för std::vector and possibly others: minimal initalization henrikv <henrik.vallgren@stream-space.com> - 2012-03-25 23:14 -0700
      Re: Request för std::vector and possibly others: minimal initalization Jason McKesson <jmckesson@gmail.com> - 2012-03-24 19:27 -0700
      Re: Request för std::vector and possibly others: minimal initalization Pedro Lamarão<pedro.lamarao@gmail.com> - 2012-03-29 12:28 -0700
        Re: Request för std::vector and possibly others: minimal initalization Daniel Krügler <daniel.kruegler@googlemail.com> - 2012-03-29 13:17 -0700

csiph-web