On Aug 9, 2004, at 10:26 AM, Alexander Terekhov wrote:
Yes, but this scheme has a drawback. "Serial wakes across context switching" (in addition to locking across context switching). For alternative, see (for example)
http://groups.google.com/groups?selm=3D9196B2.9BC29299%40web.de (Subject: Re: rwlock using pthread_cond)
The alternative in this link looks very familiar. I'm currently using two condition variables, an unsigned, and two bools (oh, and of course the mutex). Although after looking at your example I think I could probably merge my unsigned and two bools into an int and one bool (because of padding, may not be worth the effort though). My two condition variables are used slightly differently than yours because of the additional requirements of: start_upgradable() end_upgradable() ( and of course there's the conversion-functions: http://home.twcny.rr.com/hinnant/cpp_extensions/ threads.html#unlock_and_lock_sharable ) Sorry I can't just show the code. -Howard