Roland Schwarz wrote:
Yuval Ronen wrote:
I will gladly put my code here to be scrutinized by the experts on this forum (after the weekend, as the code is at work, and I'm at home now :-) ), but I fear that they will little incentive to do it.
Can't tell. Possibly yes. You will need to try.
I'll try.
Ok, I'm afraid I didn't explain myself properly. Apologies for that. What I mentioned only briefly, and had to emphasize more, is that the call to notify() will check to see if the mutex is locked - the mutex that was passed in the ctor, and throw an exception if not. The wait() function does it already, except that it should be changed to check the stored mutex&.
I hope this explanation helps answering your questions above.
If it is only about protecting the user from as you say "bad usage", where is the problem? If you need this behavior you easily can write a little convenience-wrapper for your projects that achieves this goal. The threading library is designed to allow you the broadest valid usage, only protecting from agreed misuses. Why should we unnecessarily limit the libraries API when you can specialize it to your needs?
It's true I can write a wrapper to do what I want (I'll need to write a lock class which doesn't do any locking/unlocking, but only return true to an is_locked() question, which is not very pretty, but still feasible). The thing is that I thought I wasn't limiting any valid usages, and all users of the library can benefit from this change. We obviously disagree about that crucial point.
And even if you might find out that there is a way on windows where your proposed change allows for a faster implementation, you still would need to prove that this also holds for other operating systems.
I intended to show that it's faster on Windows, and not any slower on other platforms. That should be enough, performance-wise. Peter showed that I'm avoiding some possible optimizations, which makes it slower on some platforms. As I said, should this optimization issue affect the interface might just be another issue we disagree about. In face of all this disagreement, well, what can a guy do...