1  #include <stdarg.h>
       2  
       3  extern void abort (void);
       4  extern void exit (int);
       5  
       6  void bar (int n, int c)
       7  {
       8    static int lastn = -1, lastc = -1;
       9  
      10    if (lastn != n)
      11      {
      12        if (lastc != lastn)
      13  	abort ();
      14        lastc = 0;
      15        lastn = n;
      16      }
      17  
      18    if (c != (char) (lastc ^ (n << 3)))
      19      abort ();
      20    lastc++;
      21  }
      22  
      23  #define D(N) typedef struct { char x[N]; } A##N;
      24  D(0) D(1) D(2) D(3) D(4) D(5) D(6) D(7)
      25  D(8) D(9) D(10) D(11) D(12) D(13) D(14) D(15)
      26  D(16) D(31) D(32) D(35) D(72)
      27  #undef D
      28  
      29  void foo (int size, ...)
      30  {
      31  #define D(N) A##N a##N;
      32  D(0) D(1) D(2) D(3) D(4) D(5) D(6) D(7)
      33  D(8) D(9) D(10) D(11) D(12) D(13) D(14) D(15)
      34  D(16) D(31) D(32) D(35) D(72)
      35  #undef D
      36    va_list ap;
      37    int i;
      38  
      39    if (size != 21)
      40      abort ();
      41    va_start (ap, size);
      42  #define D(N)					\
      43    a##N = va_arg (ap, typeof (a##N));		\
      44    for (i = 0; i < N; i++)			\
      45      bar (N, a##N.x[i]);
      46  D(0) D(1) D(2) D(3) D(4) D(5) D(6) D(7)
      47  D(8) D(9) D(10) D(11) D(12) D(13) D(14) D(15)
      48  D(16) D(31) D(32) D(35) D(72)
      49  #undef D
      50    va_end (ap);
      51  }
      52  
      53  int main (void)
      54  {
      55  #define D(N) A##N a##N;
      56  D(0) D(1) D(2) D(3) D(4) D(5) D(6) D(7)
      57  D(8) D(9) D(10) D(11) D(12) D(13) D(14) D(15)
      58  D(16) D(31) D(32) D(35) D(72)
      59  #undef D
      60    int i;
      61  
      62  #define D(N)					\
      63    for (i = 0; i < N; i++)			\
      64      a##N.x[i] = i ^ (N << 3);
      65  D(0) D(1) D(2) D(3) D(4) D(5) D(6) D(7)
      66  D(8) D(9) D(10) D(11) D(12) D(13) D(14) D(15)
      67  D(16) D(31) D(32) D(35) D(72)
      68  #undef D
      69  
      70    foo (21
      71  #define D(N) , a##N
      72  D(0) D(1) D(2) D(3) D(4) D(5) D(6) D(7)
      73  D(8) D(9) D(10) D(11) D(12) D(13) D(14) D(15)
      74  D(16) D(31) D(32) D(35) D(72)
      75  #undef D
      76        );
      77    exit (0);
      78  }