Subj : Re: Challenge: Multithreading & Synchronization
To   : comp.programming.threads
From : Sergei Organov
Date : Wed May 18 2005 07:58 pm

"Uenal Mutlu" <520001085531-0001@t-online.de> writes:

[...]

> class Locker
> {
> public:
>   Locker(mutex& Am) : m(Am) { m.lock();   }
>   ~Locker()                 { m.unlock(); }
> private:
>   mutex& m;
> };
> 
> Locker then can be used for both mutex and rmutex.
> This is because rmutex is derived from mutex.

Do you understand that it's wrong provided the following definitions
from your challenge hold:

> // non-recursive mutex:
> class mutex
> {
> public:
>   mutex()               { /*..*/ }
>   ~mutex()              { /*..*/ }
>   void lock()           { /*..*/ }
>   void unlock()         { /*..*/ }
>   [...]
> };
> 
> // recursive mutex:
> class rmutex : public mutex
> {
> public:
>   rmutex()        { /*..*/ }
> };

Do you understand that (public) derivation of rmutex from mutex is
broken OO design in the first place?

Anyway, why do you mix OO-issues that you don't seem to understand well,
C++ issues that you don't seem to understand well, and threads related
issues that you don't seem to understand well in a single challenge?

-- 
Sergei.

.