Date: Wed, 9 Apr 2003 15:36:53 +0400 From: Yar Tikhiy <yar@freebsd.org> To: "Andrey A. Chernov" <ache@nagual.pp.ru> Cc: arch@freebsd.org Subject: Re: termios & non-blocking I/O Message-ID: <20030409113653.GA63770@comp.chem.msu.su> In-Reply-To: <20030408181707.GA42723@nagual.pp.ru> References: <20030408164614.GA7236@comp.chem.msu.su> <20030408181707.GA42723@nagual.pp.ru>
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On Tue, Apr 08, 2003 at 10:17:08PM +0400, Andrey A. Chernov wrote: > On Tue, Apr 08, 2003 at 20:46:14 +0400, Yar Tikhiy wrote: > > While not in disagreement with POSIX[1], such a behaviour has at > > least one unwelcome consequence: If a program has been compiled > > with ``-pthread'', the TIME counter won't work on terminal descriptors > > that are in blocking mode from the program's point of view -- read(2) > > will instantly return 0 on them. That is because the following > > scenario will happen: > ... > > > Shouldn't both TIME and MIN cases be uniform in returning -1/EAGAIN > > on non-blocking descriptors? > > It means that libc_r MIN/TIME handling should be fixed to conform POSIX > and not general MIN/TIME handling way. Not exactly, I'm afraid. If the system returns 0 from read(), libc_r has nothing else to do but to pass this 0 to the application because it may be the EOF sign. Of course, the issue is more complex then I outlined, as Bruce Evans has pointed out. However, why to treat TIME differently from MIN in the system? -- Yar
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