Variadic macro and trailing comma
Short answer, yes, it is possible in a portable way.
Long answer: it's complicated, and you probably don't want to implement this yourself. There are ways to count the arguments that a macro receives and then take action according to that number. P99 implements a series of macros that can help you to achieve this. If you'd implement two base macros send_2
and send_more
for the two cases you could then implement send
as
#define send(...) \
P99_IF_LT(P99_NARG(__VA_ARGS__), 3) \
(send_2(__VA_ARGS__)) \
(send_more(__VA_ARGS__))
Technically these constructs in P99 have a restriction that they can't handle more than 150 (or so) arguments to send
.
BTW, you know that probably, calling a macro send
is not really a good idea. Usually people prefer that macros are in all-caps. Also most of the time it is a good idea to have a name prefix that is unique to your library/package, such as AC245_SEND
.