From mboxrd@z Thu Jan 1 00:00:00 1970 From: Akira Fujita Subject: Re: [RESEND][PATCH] sendfile.2: Fix description of the out_fd Date: Fri, 16 Sep 2011 08:21:48 +0900 Message-ID: <4E72888C.7010403@rs.jp.nec.com> References: <4D771705.1020408@rs.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Cc: linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-man@vger.kernel.org Hello Michael, Thank you for your work! Regards, Akira Fujita (2011/09/12 1:00), Michael Kerrisk wrote: > Hello Akira, > > 2011/3/9 Akira Fujita: >> commit cc56f7de7f00d188c7c4da1e9861581853b9e92f made >> sendfile(2) can work with any output file. >> Therefore the out_fd of sendfile(2) can refer to any file, >> but current manual (man-pages-3.32) has not been changed so far. > > Thank you for this report! Some notes below. > >> Signed-off-by: Akira Fujita >> --- >> sendfile.2 | 16 +++++++++------- >> 1 file changed, 9 insertions(+), 7 deletions(-) >> --- man-pages-3.32-a/man2/sendfile.2 2010-12-03 16:01:59.000000000 +0900 >> +++ man-pages-3.32-b/man2/sendfile.2 2011-03-09 10:34:53.000000000 +0900 >> @@ -87,15 +87,17 @@ and the file offset will be updated by t >> .I count >> is the number of bytes to copy between the file descriptors. >> >> -Presently (Linux 2.6.9): >> -.IR in_fd , >> +.IR in_fd >> must correspond to a file which supports >> .BR mmap (2)-like >> operations >> -(i.e., it cannot be a socket); > > You removed that piece, but I believe nothing changed for 'in_fd', so > I kept that piece. > >> -and >> -.I out_fd >> -must refer to a socket. >> +(i.e., it cannot be a socket). >> + >> +.IR out_fd >> +was required to be a socket, but since Linux 2.6.33 it can be >> +any file. If it is a regular file, then >> +.BR sendfile() >> +changes its offset appropriately. >> >> Applications may wish to fall back to >> .BR read (2)/ write (2) >> @@ -165,7 +167,7 @@ to minimize the number of packets and to >> >> In Linux 2.4 and earlier, >> .I out_fd >> -could refer to a regular file, and >> +could also refer to a regular file, and >> .BR sendfile () >> changed the current offset of that file. > > For 3.33 I applied a slightly modified version of you patch; see below. > > Cheers, > > Michael > > --- a/man2/sendfile.2 > +++ b/man2/sendfile.2 > @@ -92,10 +92,14 @@ The > argument must correspond to a file which supports > .BR mmap (2)-like > operations > -(i.e., it cannot be a socket); > -and > +(i.e., it cannot be a socket). > +In Linux kernels before 2.6.33, > .I out_fd > must refer to a socket. > +Since Linux 2.6.33 it can be any file. > +If it is a regular file, then > +.BR sendfile() > +changes the file offset offset appropriately. > > Applications may wish to fall back to > .BR read (2)/ write (2) > @@ -165,7 +169,7 @@ to minimize the number of packets and to tune performance. > > In Linux 2.4 and earlier, > .I out_fd > -could refer to a regular file, and > +could also refer to a regular file, and > .BR sendfile () > changed the current offset of that file. > > -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html