Re: [boost] [thread] is there an interest on this unique_to_shared_mutex_adapter class?

From: Anthony Williams (anthony.ajw_at_[hidden])
Date: 2008-05-30 06:40:59

"Phil Endecott" <spam_from_boost_dev_at_[hidden]> writes:

> vicente.botet wrote:
>> template <typename Lockable>
>> class shared_lockable_adapter
>> {
>>     shared_lockable_adapter(Lockable& mtx): mtx_(mtx) {}
>>     ~shared_lockable_adapter() {}
>>     void lock_shared() {mtx_.lock();}
>>     void unlock_shared() {mtx_.unlock();}
>>     bool try_lock_shared() { return mtx_.try_lock();}
>>     void lock() {mtx_.lock();}
>>     void unlock() {mtx_.unlock();}
>>     bool try_lock() { return mtx_.try_lock();}
>>     // other functions ....
>> private:
>>     Lockable& mtx_;
>> };
>
> So this is a trivial adapter that makes a shared mutex that can't 
> actually be shared.

I'm not sure this is such a good idea, as it wouldn't really be
shareable.

> It would also be possible, I think, to make an adapter that actually 
> creates a shared mutex from a normal one.  I've never had to write a 
> read/write mutex but I guess that this is how they are implemented internally.

It's a bit more complicated than that. boost::shared_mutex is
implemented on top of boost::mutex and boost::condition_variable for
pthreads: take a look.

Anthony
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