Overall I really like the work you've done here. I have a question about the scheduling of shared v. exclusive locks on shared_mutex. Suppose I have several shared locks already established and then an exclusive lock is tried. Are subsequent shared lock attempts deferred until after theexclusive lock has released? Or is the exclusive lock deferred until after all shared locks (regardless of when they were made) are released? Or is this even defined? It may be easiest to just leave the scheduling undefined, and perhaps that is the intent of the proposal. Whether it's defined or not, though, it should be documented. It might be useful, however, if the scheduling policy were configurable. It seems that such a policy could be established on the shared_mutex itself. Again, this is really excellent and I'm genuinely excited to see this progress. Thanks for all the hard work! -- Austin Bingham Signal & Information Sciences Laboratory Applied Research Laboratories, University of Texas at Austin 10000 Burnet Rd., Austin, TX 78758 email: abingham@arlut.utexas.edu cell: (512) 799-2444 office: (512) 835-3832