Date: 2007-06-01 14:53:14
From: Andy <atompkins_at_[hidden]>
> There was opposition to using static objects because of threading
> concerns. I do want a function that doesn't require the user to create
> a random number generator themselves.
> If I use a static engine, I need to protect it with a mutex. This is
> not optimal because there is the overhead of locking and unlocking the
> mutex. Some people would rather have a static engine per thread using
> thread local storage. This still requires one to link with
> Boost.Thread. I created the uuid::create(Engine) function (great advice
> from this list) so that users could do whatever they want (static engine
> per thread, use thread local storage,...).
> The uuid::create() function should handle the common case and not be
> best for all situations. So, I guess I need help to determine what the
> common case is.
My vote is to use a static in uuid::create() for performance, put in the documentation that this function is not thread-safe, and simply require that applications that care about thread safety for UUID creation use the uuid::create(Engine) interface. Developers going from a non-threaded to a threaded application are going to have to audit their code for thread safety anyway.
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