Geoffrey Thorpe <ge...@geoffthorpe.com>: First, you're right, pthreads_locking_callback() is collapsing everything > to a mutex. >
I was well aware of this and thought we did this for compatibility reasons (because I couldn't think of any other reasonable explanation, I guess). If actual read-write locks are just as portable, I think it's a no-brainer that we should switch to them. (After all, our code is already prepared for that, for applications that provide appropriate custom callbacks. It's just the default that falls behind.) For future work, a lock-free approach (using thread-local storage?) certainly might make sense, but switching to read-write locks in the default callbacks should be a tiny change with significant benefits to multithreaded applications. Bodo
