Hi Roberto, > Michael Kerrisk wrote: > > > Von: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> > > > /usr/share/man/man2/open.2.gz has (under O_NONBLOCK): > > > "This mode need not have any effect on files other than FIFOs." > > > > > > I'm almost sure that statement is false. > > > O_NONBLOCK prevents blocking on any filehandle (files, sockets, > > > fifos, devices, ...). > > > > Justin is on the right track in mentioning the "standard" > > behavior of O_NONBLOCK. And you haven't got things quite > > right -- for example, O_NONBLOCK can't be used for open() with > > sockets, because we can't open() a socket, and O_NONBLOCK has > > no meaning for regular files (it is just silently ignored). > > Yes, the de jure standard as susv3 may say is that, but the de facto > standard as _any_ modern UNIX does is the same for every type of file. > > > But I agree that the man page is a bit misleading. One might > > get the impression that, for example, O_NONBLOCK can't be used > > for sockets, although we can enable O_NONBLOCK on a socket using > > fcntl(). And O_NONBLOCK does have meaning for some devices, > > and sometimes has an effect for regular files. > > O_NONBLOCK _always_ has an effect for regular files, it prevents > blocking on read or write operations (as an example think in NFS or slow > disks)
I'm not sure of the details for NFS, and probably I don't need to worry about them anyway, as far as this page is concerned. But what do you mean by a "slow disk"? > > I have made the following changes: > > > > * Removed that sentence from open.2 ;-). > > > > * Added a sentence noting that the effect of O_NONBLOCK > > for file locks and leases is described in fcntl.2. > > > > * Somewhat expanded the discussion of mandatory locking in > > fcntl.2. > > > > The changes will appear in upstream 2.29. > > You may always want to attach the patch or an URL for review. 2.29 should be out in a week or so, and I'll send a mail when it is released; could you let me know then if anything still needs fixing in your opinion. > Thanks for these changes. I already knew they were misleading to many > people. De nada. Michael -- Michael Kerrisk maintainer of Linux man pages Sections 2, 3, 4, 5, and 7 Want to help with man page maintenance? Grab the latest tarball at ftp://ftp.win.tue.nl/pub/linux-local/manpages/, read the HOWTOHELP file and grep the source files for 'FIXME'. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
