/*
 * Testcase for a possible compiler bug:
 * structure with flexible array member.
 * offsetof(struct,flexible_member) != sizeof(struct).
 *
 * That seems to be a violation of 6.7.2.1, constraint 16 of the C99
 * standard:
 * "First, the size of the structure shall be equal to the offset of the
 * last element of an otherwise identical structure that replaces the
 * flexible array member with an array of unspecified length.
 */
#include <stdio.h>

/*
 * structure: sizeof() = 4.
 * alignment: 2, due to the short.
 */
struct pollfd {
	short fd;
	char events;
	char revents;
};

/*
 * sizeof: 12
 * alignment: 4, due to the int.
 */
struct n2 {
	/* offset 0 */
	int m;
	/* offset 4 */
	char n;
	/* one byte padding, 'struct pollfd' requires 2 byte alignment */
	/* offset 6 */
	struct pollfd a[1];
	/* offset 10: two bytes padding for 4 byte alignment,
	 * required for the int in this structure */
};

/*
 * sizeof: 8.
 * XXX
 * Is this correct?
 * offsetof(struct n1, a) is 6
 * --> offsetof(struct n1, a) != sizeof(struct n1)
 * XXX
 */
struct n1 {
	/* offset 0 */
	int m;
	/* offset 4 */
	char n;
	/* one byte padding, 'struct pollfd' required 2 byte alignment */
	/* offset 6 */
	struct pollfd a[];
};
	
#define offsetof(a,b) \
		(int)&((a*)NULL)->b

int main(void)
{
	printf("pollfd: sizeof: %d.\n", sizeof(struct pollfd));
	printf("fix: sizeof: %d, offsetof: %d.\n", sizeof(struct n2), offsetof(struct n2, a));
	printf("var: sizeof: %d, offsetof: %d.\n", sizeof(struct n1), offsetof(struct n1, a));
	return 0;
}