site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com After studying Terry's latest remarks I realize where the real "bug" is. It seems that Posix semaphores on Mac OS X have limitations, are not supported and not recommended. Probably their only use is to allow porting of linux programs. So the bug is that man pages for the sem_xxx() methods lack a statement saying that these functions are depracated and not recommended for new designs. They aren't deprecated, we just don't promise that they are fully POSIX compliant at this time. Other than that, yeah, there's a man page. 8-). -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... On Apr 1, 2009, at 12:31 PM, David Gatwood wrote: On Mar 31, 2009, Terry Lambert wrote: On Mar 31, 2009, at 8:21 PM, Jerry Krinock wrote: Would anyone disagree with this? Hmm. I just checked and I see nothing in the POSIX spec for sem_wait/sem_post that requires such behavior. Maybe there's something elsewhere and I just missed it---not sure---but I think Mac OS X may be compliant and correct as-is. It looks like the only guaranteed cross-platform and safe way to handle this situation would be to add a signal handler that calls sem_post(...) and then _exit(255) if you get a SIGSEGV or SIGBUS signal. We don't support unnamed POSIX semaphores, we don't support sem_getvalue(), and if you try you get a SIGSYS, which if you don't catch it, you're program exits. We also don't guarantee correct error semantics for the POSIX named semaphores we do have, since if we can't run the conformance tests because we don't support unnamed semaphores, we can't tell if the errors we return are correct or not. For future reference, "supported" in POSIX terms is whether or not there's a 200112L value for the manifest constant for the subssytem in <unistd.h>. This email sent to site_archiver@lists.apple.com