Date: Fri, 09 Nov 2001 15:29:18 -0800 From: Peter Wemm <peter@wemm.org> To: Bill Fenner <fenner@research.att.com> Cc: bde@zeta.org.au, alfred@FreeBSD.org, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/fs/fifofs fifo_vnops.c Message-ID: <20011109232918.95638380A@overcee.netplex.com.au> In-Reply-To: <200111091803.KAA24774@windsor.research.att.com>
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Bill Fenner wrote: > > POSIX FIFOs seem relatively useless, unless there's always a > writer present. Without a writer, a reader has to spin (either > in select+read or just read) until a writer is present. > > I can't tell if POSIX really defined FIFOs to be useless, or we're just > misinterpreting the standards-speak. I'd prefer if an "empty FIFO with > no writers" was really an "empty FIFO with no writers where the EOF > condition hasn't been delivered yet"; then read() could block (or return > EAGAIN or EWOULDBLOCK) when there were no writers yet, and could go back > to that condition after the EOF of all the writers leaving was delivered. I would prefer something that didn't violate POLA than something that was strictly standards conformant but useless. Being useless certainly violates POLA. :-) Especially when most of the other significant players have decided to go for the 'working' option rather than the compliant-but-useless option. Windows NT's POSIX compatability-box was also in the compliant-but-useless category too. Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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