On Thu, Nov 26, 2015 at 02:56:30PM +0100, Hannes Frederic Sowa wrote:

quoted

+#define DECLARE_NLREQ(name, hdrname, payload, tailroom)                       \
+	struct {                                                              \
+		struct nlmsghdr hdrname;                                      \
+		payload;                                                      \
+		char __b[tailroom] __attribute__((aligned(NLMSG_ALIGNTO)));   \
+	} name = { .hdrname = {                                               \
+		.nlmsg_len = (unsigned long)&name.__b - (unsigned long)&name, \

offsetof(typeof(name), __b) ?

Ah, thanks! I already considered offsetof(), but the fact it needs a
type name and the declared struct is anonymous appeared unsolvable to
me. Good to know typeof() can be used this way!

Thanks, Phil