Re: [Algorithms] C++ inherited constructors

[<ma...@ci...>]

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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