Date: Sat, 16 Oct 2004 09:50:55 -0500 From: Ryan Sommers <ryans@gamersimpact.com> To: Carl J <carlj1752@hotmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: open() vs the lowest unused file descriptor Message-ID: <4171354F.9090400@gamersimpact.com> In-Reply-To: <BAY15-F3OUIHNkjgJKV000007b3@hotmail.com> References: <BAY15-F3OUIHNkjgJKV000007b3@hotmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Carl J wrote: > Hi! > > Today I noticed that on Single Unix Specification V2, > as well as on the Linux 2.4.26 machine I have here, > that the open() call promises to return the lowest > unused file descriptor when successful. > > I'm just wondering: does FreeBSD 4.x and 5.x promise > that? If so, should we update the manpage > to match SUSv2 more closely? > > Thank you! > > - Carl 4.x I'm pretty sure about 5.x I know does. This isn't a new thing. Since as far back as I can remember the UNIX semantics have been to return the lowest unused fd on an open(2) call. This has also been the subject of much discussion as finding the first free descriptor can cost a lot of processing power for applications that use large numbers of descriptors. FreeBSD uses a bitmap with hints I believe. All code would be in sys/kern_descrip.c. -- Ryan Sommers ryans@gamersimpact.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4171354F.9090400>