Re: [Boost-users] [Thread] Trying to share a mutex between objects

From: Adam Nielsen (adam.nielsen_at_[hidden])
Date: 2008-07-15 21:35:11

>> My idea was to create a mutex for this (lock before the call, unlock 
>> after it)...
> I think I'd probably create a class to manage access to the shared 
> function. The class would contain the mutex, and the method that calls 
> the C function would instantiate the lock object. Nobody else would 
> directly call the C function any more.

I ended up reaching the same conclusion here, as I wanted to store other 
persistent data too (in this case a counter for the number of times the 
function was called) and wrapping it all up in a class does make it 
cleaner, as you suggest.

> Since you already have a way to pass mutex references to your handful of 
> objects, though, you could pass a reference to your wrapper object 
> instead.

Yes, I think I prefer this method, as I would rather choose to only have 
one instance of the class floating around, as opposed to using a 
Singleton pattern with its additional complexity to enforce this rule. 
(I'd never heard of the Singleton pattern before - interesting!)

> I'd probably allocate it on the heap, pointing to it with a 
> boost::shared_ptr. Store a copy of that boost::shared_ptr in each of 
> your handful of objects. Ownership is shared among them, and the last 
> one to leave turns out the lights.

I agree - however this time it will be around for the life of the 
(fairly simplistic) program, so it'll be just as easy to create it as a 
local variable in main(), wait for the threads to terminate and then 
have it destroyed automatically.

Thanks for your reply!

Cheers,
Adam.