Date: Mon, 30 Aug 2004 12:38:42 -0700 (PDT) From: Don Lewis <truckman@FreeBSD.org> To: tijl@ulyssis.org Cc: freebsd-stable@FreeBSD.org Subject: Re: 4-stable termios diff behaviour lc/lc_r Message-ID: <200408301938.i7UJcg4j018717@gw.catspoiler.org> In-Reply-To: <20040830204553.0046ca41.tijl@ulyssis.org>
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On 30 Aug, Tijl Coosemans wrote: > I've done some more testing. It appears that when linked with lc_r, > VTIME is completely ignored. > > As explained in termios(4), when VMIN>0, the read call will wait > indefinitely for the first byte and then use VTIME as an interbyte > timer. When using lc_r however, it'll return immediately after the > first couple bytes read, even if that's less than VMIN. > > The case where VTIME==0 works as it should both with lc and lc_r. This is not suprising. The way libc_r handles I/O is that it puts all the descriptors in non-blocking mode and uses poll() to figure out which threads to run. To work properly, libc_r would have to emulate VMIN internally. > I dont have access to a box with -current, so I can't say if the same > applies to it. I would expect the same behaviour with libc_r on -CURRENT, but the other thread libraries should work properly. > I hope somebody understands this better or could at least give me a > few pointers as to where to look in the source code. > > Thanks, tijl
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