From 5159c34ea8923bf0c17fd31e183c5803b72b97f3 Mon Sep 17 00:00:00 2001 From: Thomas Haller Date: Mon, 5 Feb 2018 13:10:24 +0100 Subject: [PATCH 2/2] ovs: fix compiler error for passing NMDevice pointer to NM_DEVICE_OVS_INTERFACE_GET_PRIVATE() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit NM_DEVICE_OVS_INTERFACE_GET_PRIVATE() is implemented via the _NM_GET_PRIVATE() macro. This macro uses C11's _Generic() to provide additional compiler checks when casting from an incompatible pointer type. As such, NMDevice *device = ...; NMDeviceOvsInterfacePrivate *priv; priv = NM_DEVICE_OVS_INTERFACE_GET_PRIVATE (device); causes a compilation error: error: ‘_Generic’ selector of type ‘NMDevice * {aka struct _NMDevice *}’ is not compatible with any association One workaround would be to cast the pointer first: priv = NM_DEVICE_OVS_INTERFACE_GET_PRIVATE ((NMDeviceOvsInterface *) device); A better fix is to mark NMDevice as a compatible pointer in _NM_GET_PRIVATE(), which this patch does. Previously, this went unnoticed, because due to bug "a43bf3388 build: fix configure check for CC support of _Generic() and __auto_type", we failed to detect support for _Generic() when compiling with -Werror. That essentially disables this check, and NM_DEVICE_OVS_INTERFACE_GET_PRIVATE() would do a direct cast. A workaround for this build failure might be to build with -Werror, which accidentally results in not using _Generic(). https://bugzilla.gnome.org/show_bug.cgi?id=793183 Fixes: 8ad310f8e3cb0157cfa5fa8ff10f313555cf8e3c (cherry picked from commit 782578122c6cb23bdbee0b01eddceee1b967a673) --- src/devices/ovs/nm-device-ovs-interface.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/devices/ovs/nm-device-ovs-interface.c b/src/devices/ovs/nm-device-ovs-interface.c index e746a3fd2..ce32c2dd7 100644 --- a/src/devices/ovs/nm-device-ovs-interface.c +++ b/src/devices/ovs/nm-device-ovs-interface.c @@ -50,7 +50,7 @@ struct _NMDeviceOvsInterfaceClass { G_DEFINE_TYPE (NMDeviceOvsInterface, nm_device_ovs_interface, NM_TYPE_DEVICE) -#define NM_DEVICE_OVS_INTERFACE_GET_PRIVATE(self) _NM_GET_PRIVATE (self, NMDeviceOvsInterface, NM_IS_DEVICE_OVS_INTERFACE) +#define NM_DEVICE_OVS_INTERFACE_GET_PRIVATE(self) _NM_GET_PRIVATE (self, NMDeviceOvsInterface, NM_IS_DEVICE_OVS_INTERFACE, NMDevice) /*****************************************************************************/ -- 2.14.3