Date: Wed, 21 Dec 2011 12:25:18 -0500 From: John Baldwin <jhb@freebsd.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: mdf@freebsd.org, Robert Watson <rwatson@freebsd.org>, current@freebsd.org Subject: Re: extattr_set_*() return type Message-ID: <201112211225.18581.jhb@freebsd.org> In-Reply-To: <20111221161310.GW50300@deviant.kiev.zoral.com.ua> References: <201112201649.06265.jhb@freebsd.org> <201112211031.11977.jhb@freebsd.org> <20111221161310.GW50300@deviant.kiev.zoral.com.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wednesday, December 21, 2011 11:13:10 am Kostik Belousov wrote: > On Wed, Dec 21, 2011 at 10:31:11AM -0500, John Baldwin wrote: > > On Tuesday, December 20, 2011 5:18:58 pm mdf@freebsd.org wrote: > > > On Tue, Dec 20, 2011 at 1:49 PM, John Baldwin <jhb@freebsd.org> wrote: > > > > Hmm, if these functions are expected to operate like 'write(2)' and are > > > > supposed to return the number of bytes written, shouldn't their return value > > > > be 'ssize_t' instead of 'int'? It looks like the system calls themselves > > > > already do the right thing in setting td_retval[] (they assign a ssize_t to it > > > > and td_retval[0] can hold a ssize_t on all of our current platforms). It > > > > would seem that the only change would be to the header and probably > > > > syscalls.master. I guess this would require a symver bump to fix though. > > > > > > An extended attribute larger than 2GB is a programming abuse, though. > > > Technically int may not be 32 bits but it is on all supported > > > platforms now. > > > > Today it is an abuse. In the 90's a 64-bit off_t was considered an abuse by > > some. :) > > > > The type should match the documented behavior. On OS X the set operation > > doesn't return a size but instead returns a simple success/failure (0 or -1) > > for which an int is appropriate. However, the FreeBSD API documents that it > > operates like write and consumes the buffer. Note that the size of the > > buffer passed to the 'set' and 'get' operations is a size_t, not an int, and > > the 'get' operations already return a ssize_t, not an int. > > Note that read(2)/write(2) do return int. I still have WIP patch to fix > this, but after some conversations with Bruce I am not sure it is worth > finishing. The manpages and /usr/include/unistd.h claim they return ssize_t. Is this related to the changes to make uio_resid a size_t (I thought that went into the tree)? If the problem is that the values read/write return may fall into the range of only an int even on 64-bit platforms, that is different from the return type which is part of the ABI. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201112211225.18581.jhb>