Re: [Algorithms] C++ inherited constructors

[Matt A. <de...@gm...>]

Yes, this is what I actually did.
But I'm really thinking about the things Adam was saying
maybe I should have a deeper look at me overall object structure.
Currently I'm seeking some better OO-guidelines for a redesign -
I want to avoid regularly ending up with problems due to a
weak class design
But of course Stephen Baker is right, and this list is not
the right place to discuss it in all details
( Sorry, I didn't realize this'll be such a long thread )
Btw. thanks for the info about sweng-gamedev list, Scott
Maybe that'll prevent some OT questions like mine in future;)

Matt

----- Original Message -----
From: Mark Atkinson <ma...@ci...>
To: <gda...@li...>
Cc: <ma...@ci...>
Sent: Tuesday, July 18, 2000 1:48 PM
Subject: Re: [Algorithms] C++ inherited constructors


> You can always make the ctor throw an exception, which is an acceptable
form
> of error handling in this case.
>
> Matt, I think the solution to the problem is to add another constructor to
> your main-threadloop-class and your CThread which take an existing thread
> handle, e.g.:
>
> class MainThreadLoop
> {
>     MainThreadLoop(HANDLE hThread) : CThread(hThread) /*,
m_x(0)*/{/*etc*/}
> };
>
> class CThread
> {
>    CThread()               { /* create a thread */ }
>    CThread(HANDLE hThread) { /* use given thread */ }
>
>    /* or: CThread(HANDLE hThread=0)
>           {
>               if (hThread==0) { hThread = CreateThread(...); }
>           } */
> };
>
> WinMain(...)
> {
>    MainThreadLoop MainLoop(GetCurrentThread());
> }
>
>
> -=Mark=-
>
> Mark Atkinson, Technical Director, Computer Artworks Ltd.
> http://www.artworks.co.uk
>
>
> > That, together with the fact that constructors can't return error codes
> > (only throw exceptions) when something goes wrong, has me following a
very
> > simple design heuristic ever since I can remember:  Don't make a
> > constructor
> > do anything other than initializing member variables.  In other words,
> > don't
> > let it do anything that can go wrong.  Put that code (for example the
> > thread
> > creation code in your case) in another method that has to be called
after
> > construction.  If you had done that when you designed the CThread class,
> > you
> > wouldn't have a problem.
> > --
> > --Adam Moravanszky
> > http://www.n.ethz.ch/student/adammo
> >
> > -----Original Message-----
> > From: Matt Adams <de...@gm...>
> > To: gda...@li...
> > <gda...@li...>
> > Date: Saturday, July 15, 2000 1:19 PM
> > Subject: Re: [Algorithms] C++ inherited constructors
> >
> >
> > >I need this for aesthetic reasons :)
> > >I've got an abstract CThread class. If a want to create a new thread, I
> > >build my process class and inherit CThread, which creates a new thread
by
> > >construction.
> > >Now I want my main-threadloop-class to inherit CThread, too, to provide
> > all
> > >the thread functionality to my main thread. But that thread already
> > exists
> > > created by compiler ), and shouldn't be created again by CThread.
> > >Of course I can put CThread () and ~CThread () in functions like
Create()
> > >and Destroy() and leave the constructor / destructor empty. But it'd be
> > >nicer if it could be done in another way...
> > >
> > >----- Original Message -----
> > >From: Favnir
> > >To: gda...@li...
> > >Sent: Saturday, July 15, 2000 1:32 PM
> > >Subject: Re: [Algorithms] C++ inherited constructors
> > >
> > >The only way you can do this is to define a (preferably) protected
> > >do-nothing constructor for the base class, and inherit it in the
subclass
> > >constructor.
> > >
> > >But, why in the world would you need to do this, in the first place?
> > >
> > >Are,
> > >F
> > >
> > >----- Original Message -----
> > >From: Matt Adams
> > >To: gda...@li...
> > >Sent: Saturday, July 15, 2000 12:22 PM
> > >Subject: [Algorithms] C++ inherited constructors
> > >
> > >
> > >Hi,
> > >
> > >I got a question about the C++ class hierarchy.
> > >
> > >class a
> > >{
> > >    a () {...}; // constr a
> > >};
> > >
> > >class b : a
> > >{
> > >    b () {...}; // constr b
> > >};
> > >
> > >b instance;
> > >
> > >When creating an instance of b, constructors for both class a and class
b
> > >are called.
> > >Is there a way to suppress the automatic calling of constructor a ?
> > >Or something like 'overloading' the old constructor by a new one ?
> > >I couldn't find anything like that in the compiler docs.
> > >
> > >Any help appreciated,
> > >Matt
> > >
> > >
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> > >
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