[Xen-devel] [PATCH 2 of 2] libxc: add comment to why NetBSD return hypercall->retval

[Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>]

# HG changeset patch
# User Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>
# Date 1326968470 -3600
# Node ID 484fb928e36c3150ed66cf102087565ded2769fd
# Parent  d7d91b1eb79edf93230713d80ac6ac7738bdd71e
libxc: add comment to why NetBSD return hypercall->retval

Added a comment that explains why NetBSD return hypercall->retval on
success.

Signed-off-by: Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>

diff -r d7d91b1eb79e -r 484fb928e36c tools/libxc/xc_netbsd.c
--- a/tools/libxc/xc_netbsd.c   Thu Jan 19 11:17:35 2012 +0100
+++ b/tools/libxc/xc_netbsd.c   Thu Jan 19 11:21:10 2012 +0100
@@ -96,6 +96,12 @@ static int netbsd_privcmd_hypercall(xc_i
     int fd = (int)h;
     int error = ioctl(fd, IOCTL_PRIVCMD_HYPERCALL, hypercall);
 
+    /*
+     * Since NetBSD ioctl can only return 0 on success or < 0 on
+     * error, if we want to return a value from ioctl we should
+     * do so by setting hypercall->retval, to mimic Linux ioctl
+     * implementation.
+     */
     if (error < 0)
         return error;
     else

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel