Date: Mon, 12 Apr 1999 12:16:12 -0700 From: Jason Thorpe <thorpej@nas.nasa.gov> To: Ville-Pertti Keinonen <will@iki.fi> Cc: dillon@apollo.backplane.com (Matthew Dillon), hackers@FreeBSD.ORG Subject: Re: read() and pread() syscalls Message-ID: <199904121916.MAA07413@lestat.nas.nasa.gov>
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On 12 Apr 1999 17:01:50 +0300
Ville-Pertti Keinonen <will@iki.fi> wrote:
> This may come as a shock to you, but read(2)/write(2) aren't atomic in
> updating the file pointer, either.
Then that's a bug in the FreeBSD kernel.
> Actually, read(2) is equivalent to lseek(2)+pread(2)+lseek(2), with the
> last lseek(2) being SEEK_CUR by the read count returned by pread(2).
> The difference is that read(2) can only be pre-empted if it blocks
> doing I/O (which is not unusual).
Geez, how did this get implemented in FreeBSD?! It's certainly not that
complicated.
-- Jason R. Thorpe <thorpej@nas.nasa.gov>
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