Re: [libvirt] [PATCH] MacOS: Handle changes to args in xdrproc_t

On Tue, Oct 29, 2013 at 6:28 PM, Eric Blake <eblake(a)redhat.com&gt; wrote: > On 10/28/2013 12:05 PM, Doug Goldstein wrote: >> With Mac OS X 10.9, xdrproc_t is no longer defined as: >> >> typedef bool_t (*xdrproc_t) (XDR *, void *, ...); >> >> but instead as >> >> typedef bool-t (*xdrproc_t) (XDR *, void *, unsigned int); >> >> The rationale explained in the header is that using a vararg is >> incorrect and has a potential to change the ABI slightly. They decided >> to specify the exact number of parameters and for compatibility with old >> code decided to make the signature require 3 arguments. The third >> argument is ignored for cases that its not used and its recommended to >> supply a 0. >> --- >> configure.ac | 41 +++++++++++++++++++++++++++++++++++++++++ >> src/rpc/virnetmessage.c | 10 ++++++++-- >> 2 files changed, 49 insertions(+), 2 deletions(-) >> > > I'd like some feedback from someone else who can actually test this on > MacOS, as well as FreeBSD, but it does seem reasonable to get in 1.1.4. Gave this a change a whirl on FreeBSD 9.2 and it was fine. But obviously more testing is better.

>> + AC_DEFINE_UNQUOTED([XDRPROC_T_ARG_COUNT], [$lv_cv_xdrproc_t_args], >> + [number of arguments that xdrproc_t func ptr takes]) > > Seems reasonable; but I'm a bit worried about accepting args=2 in the > cases where we actually needed the varargs to pass 3. It may be safer > to pass 3 always, unless we have empirical evidence that uclibc will > fail to compile if we don't limit to exactly 2 (and not just a thread > archives where they were contemplating forcing just 2, but where I don't > know if the thread was actually applied as a patch). fwiw, it appears that uclibc master [1] has not gone that route so I'm not sure what became of that thread. Hard coding our implementation to always pass 3 arguments was my other approach that I had mentioned on IRC but I wasn't sure about any negative repercussions on other platforms. [1] http://git.uclibc.org/uClibc/tree/include/rpc/xdr.h#n149 -- Doug Goldstein -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list