[ros-dev] Re: [ros-diffs] [gedmurphy] 19312: Improve stopping control of the service

[Murphy, Ged (Bolton)]

> -----Original Message-----
> From: Thomas Weidenmueller [mailto:w3seek at reactos.com] 
> Sent: 17 November 2005 23:38
> To: ReactOS Development List
> Subject: Re: [ros-dev] Re: [ros-diffs] [gedmurphy] 19312: 
> Improve stopping control of the service
> 
> 
> Ged Murphy wrote:
> > Could you explain what you mean?
> As you want to change the value of the variables which are used in a
> multithreaded environment you need to used the Interlocked* 
> functions to
> ensure an atomic change in all environments (UP, MP, ...), and also to
> make sure it's portable.
> 
> > Those variables are only modified within the base thread, all other
> > threads just check the value and act upon it.
> > Why would that not be thread safe?
> You're assuming the code will only run on a x86 system. In 
> fact, as long
> as the variables are aligned properly it is an atomic operation. But
> don't forget the other architectures and possibly upcoming 
> technologies
> based on x86 that could void this assumption.
> 
> I have to admit that the code wouldn't break, even in circumstances
> where the operation wouldn't be atomic, but technically the code still
> isn't thread-safe this way.
> 
> - Thomas

This function is new to me. 
I'm just doing a bit of research on it now to better understand it, but
could you just give me a bit of background of the difference between this,
and using something like a mutex or CS, and why it's better in this
scenario?

Thanks,
Ged.




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