Re: A proposal for a fully-portable reader-writer lock

From: williamkempf_at_[hidden]
Date: 2001-04-25 09:43:47

--- In boost_at_y..., "Wayne Miller" <wcm_at_e...> wrote:
> I'd like to propose this reader-writer lock as an addition to the 
boost
> library.

Reader/writer locks are planned for Phase II of Boost.Threads.

> It supports the basic interface:
> 
> void lock();
> void unlock();
> void lock() const;
> void unlock() const;
> 
> Any number of threads are allowed into the critical section if the 
const
> version of lock is used, but at most one thread is allowed into the 
critical
> section if the non-const versions is called.

Using the const-ness of the object to distinguish between read and 
write locks is, IMHO, a very bad idea, especially since locking 
changes the object's state.
 
> The lock is implemented as a template that takes two parameters, an 
object
> type SEMAPHORE, and an object type MUTEX. These are trivial objects 
that
> both must support the interface lock and unlock.

This sort of parameterization of the type sounds very dangerous to me.

Bill Kempf