Re: [Boost-users] Why is boost::thread::mutex noncopyable?

From: Rene Rivera (grafik.list_at_[hidden])
Date: 2006-01-01 13:13:26

Phil Endecott wrote:
>>>Can someone help me to understand why boost::thread::mutex is 
>>>noncopyable?  I expect that there is a good reason, but I can't see it 
>>>at the moment.
>>
>>http://www.boost.org/doc/html/threads/faq.html#id2786688
> 
> 
> Thanks for the link.  Here is the text:
> 
> Why do Mutexes  have noncopyable semantics?
> 
> I disagree with the first comment: "The only logical form of copy would 
> be to use some sort of shallow copy semantics in which multiple mutex 
> objects could refer to the same mutex state."  What's wrong with the 
> copy of a mutex being a new independent mutex? 

Because then it's not a copy semantic, but a plain new construction.

> (There's a problem if 
> you copy a locked mutex, but I don't propose to do that.)

But what you propose will work for you only. It won't work for anyone else.

By the way you should read further down, item #6, on the FAQ for how to 
put a member mutex in a class and have the copy semantics you want. 
There even an example ;-)

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