From: Erik Faye-Lund Date: Fri, 01 Apr 2011 20:41:47 GMT Subject: Re: [PATCH 5/4] run-command: implement abort_async for pthreads Message-ID: In-Reply-To: <201104012236.12844.j6t@kdbg.org> On Fri, Apr 1, 2011 at 10:36 PM, Johannes Sixt wrote: > On Freitag, 1. April 2011, Erik Faye-Lund wrote: >> On Fri, Apr 1, 2011 at 10:05 PM, Jeff King wrote: >> > On Fri, Apr 01, 2011 at 09:57:14PM +0200, Erik Faye-Lund wrote: >> >> > But this does not help the case at hand in any way. How would you >> >> > interrupt a thread that is blocked in ReadFile()? The point of >> >> > pthread_cancel() is that it interrupts blocked system calls >> >> >> >> There is no mention of such a guarantee in POSIX (section 2.9.5 Thread >> >> Cancellation), so relying on that is undefined behavior. >> > >> > Eh? My pthreads(7) says that read() is required to be a cancellation >> > point acrroding to POSIX. I didn't dig up the actual reference in the >> > standard, though. >> >> I don't understand where the implementor would get that from after >> reading through it, but if there's something I've missed we can fix it >> by replacing my pthread_cancel with this, no? >> >> static inline int pthread_cancel(pthread_t thread) >> { >>       SetEvent(thread.cancel_event); >>       CancelSynchronousIo(thread.handle); >> } > > Do I deserve this? There *is* a function that does what we need. I get what I > deserve when I don't study all 100,000 functions in the manual... > Hey, it's mentioned in the ReadFile documentation! > Wait a minute! I *did* study 100,000 functions. This is one of the 25,000 > functions that are new in Vista... Those I haven't studied, yet. > Bah, Vista and up. That blows, we support WinXP as well! Well, dynamically loading the function when it's there is better than doing NOTHING, which was the previous alternative, no? :)