#define M_RETI_ARG27(x,y,z,aa, ...)    aa#define M_RET_ARG27(...)        M_RETI_ARG27(__VA_ARGS__)#define M_COMMA_P(...)          M_RET_ARG27(__VA_ARGS__, 1, 1, 0, useless)#define M_EMPTYI_DETECT(...)    0, 1,#define M_EMPTYI_P_C1(...)      M_COMMA_P(M_EMPTYI_DETECT __VA_ARGS__ () )#define EX#define empty(x)#define fnlike(x) yeah x/* If the following macro is called with empty arg (X183), the use   of 'x' between fnlike and '(' doesn't hinder the recognition of this   being a further fnlike macro invocation.  */#define usefnlike(x) fnlike x (x)X181 M_EMPTYI_P_C1()X182 M_EMPTYI_P_C1(x)X183 usefnlike() #define ABC(x) ABC : x#define A(a,b,c) a ## b ## c#define B(a,b,c) A(a,b,c)#define C(a,b,c) a b cB(    C(A,C(,,),),    C(B(,,),B,B(,,)),    C(B(,,),B(,,),C)    )/* */(a b c) #define TEST(x) TEST : x#define K(a,b) a ## b#define L(a,b) K( TE  a , b  ST )L(,)(t e s t)