Re: [boost] [thread] RFC standard proposed mutex, read-write mutex, condition

From: David Abrahams (dave_at_[hidden])
Date: 2007-08-22 18:31:37

on Wed Aug 22 2007, Howard Hinnant <howard.hinnant-AT-gmail.com> wrote:

> This is a class that we're proposing can be used in two different ways:

Who's "we?" Does this correspond to your proposal, or, say, Peter's
suggested modification?

> Use the default constructor and this code is legal:
>
> mutex m1;
> mutex m2;
> condition<mutex> cv;
> ...
> unique_lock<mutex> lk(m1);
> while (pred)
>     cv.wait(lk);
> ...
> unique_lock<mutex> lk(m2);
> while (pred)
>     cv.wait(lk);
>
> Simply change the condition construction to:
>
> condition<mutex> cv(m1);
>
> And all of the sudden the above code is no longer legal.  If the code  
> is legal with one constructor, what is it that makes the code a logic  
> error **100% of the time**, instead of a fixable exceptional  
> circumstance when using the second constructor?

I didn't understand any of that sentence after the word "constructor."
Could you rephrase?

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com
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