结构体中的柔性数组

$ ./a.out
   offsets: i=0; c=4; d=8 a=16
   sizeof(struct s)=16

Program source

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
   struct s {
	   int i;
	   char c;
	   double d;
	   char a[];
   };

   /* Output is compiler dependent */

   printf("offsets: i=%ld; c=%ld; d=%ld a=%ld\n",
		   (long) offsetof(struct s, i),
		   (long) offsetof(struct s, c),
		   (long) offsetof(struct s, d),
		   (long) offsetof(struct s, a));
   printf("sizeof(struct s)=%ld\n", (long) sizeof(struct s));

   exit(EXIT_SUCCESS);
}

详解：http://blog.csdn.net/code_crash/article/details/4854939