On Sat, Jan 18, 2020 at 01:09:55AM +1100, Duncan Roe wrote: [...] > diff --git a/src/internal.h b/src/internal.h > index 0cfa425..dafb33a 100644 > --- a/src/internal.h > +++ b/src/internal.h > @@ -9,6 +9,7 @@ > #else > # define EXPORT_SYMBOL > #endif > +#define PKTB_TAIL (pktb->data + pktb->len) Instead of a macro, I'd suggest you add (something like): static inline uint8_t *pktb_tail(struct pktbuff *pktb) { return pktb->data + pktb->len; } Thanks.