Re: [Libguestfs] [PATCH 3/3] lib: Add third, zero parameter to xdrproc_t

As advised by Daniel P. Berrange, the third parameter can be passed on all platforms rather than specifically Mac. Quoting a libvirt commit rationale after Daniel: commit 9fa3a8ab6fd82ad2f5a14b490696085061418718 Author: Doug Goldstein <cardoe(a)cardoe.com&gt; Date: Wed Oct 30 11:22:58 2013 -0500 MacOS: Handle changes to xdrproc_t definition With Mac OS X 10.9, xdrproc_t is no longer defined as: typedef bool_t (*xdrproc_t)(XDR *, ...); but instead as: typedef bool_t (*xdrproc_t)(XDR *, void *, unsigned int); For reference, Linux systems typically define it as: typedef bool_t (*xdrproc_t)(XDR *, void *, ...); The rationale explained in the header is that using a vararg is incorrect and has a potential to change the ABI slightly do to compiler optimizations taken and the undefined behavior. 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. --- src/proto.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/proto.c b/src/proto.c index 92ae84d..e229abb 100644 --- a/src/proto.c +++ b/src/proto.c @@ -252,7 +252,7 @@ guestfs___send (guestfs_h *g, int proc_nr, * have no parameters. */ if (xdrp) { - if (!(*xdrp) (&xdr, args)) { + if (!(*xdrp) (&xdr, args, 0)) { error (g, _("dispatch failed to marshal args")); return -1; } @@ -681,7 +681,7 @@ guestfs___recv (guestfs_h *g, const char *fn, return -1; } } else { - if (xdrp && ret && !xdrp (&xdr, ret)) { + if (xdrp && ret && !xdrp (&xdr, ret, 0)) { error (g, "%s: failed to parse reply", fn); xdr_destroy (&xdr); return -1; -- 1.9.3