Re: [boost] boost::thread and move semantics

From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2007-12-18 13:24:36

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On Tuesday 18 December 2007 11:48 am, Howard Hinnant wrote:
> That being said, a non-movable boost::mutex does not prohibit a
> wrapper around that type from being movable, if you're willing to
> accept alternative semantics.  I'm not familiar with the boost move
> library, but the C++0X syntax would simply be:
>
> class my_wrapper
> {
>      std::mutex mut_;  // or boost::mutex
> public:
>      my_wrapper() {}
>      my_wrapper(my_wrapper&&) {}  // same as default ctor
>      my_wrapper& operator=(my_wrapper&&) {return *this;}  // do nothing
>
>      void lock() {mut_.lock();}
>      bool try_lock() {return mut_.try_lock();}
>      void unlock() {mut_.unlock();}
> };

What I'm thinking of is more along the lines of

template<typename Mutex>
class my_wrapper
{
     Mutex mut_;
public:
     my_wrapper(Mutex &&mut): mut_(mut);
// ...
};

So I can have a my_wrapper<Mutex> without worrying about whether the template 
Mutex type has some weird constructor, or even if it is default 
constructible.  I guess the best I could do along those lines is to have a 
constructor that allows the user to pass in a dynamically allocated Mutex, 
which the wrapper would take ownership of.  Note, I've never really done 
anything with rvalue references or moveable types, so maybe this is an abuse 
of them?

- -- 
Frank
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