1#if __FreeBSD__ == 0		/* 1.0 did not define __FreeBSD__ */
2#define __FreeBSD_version 199401
3#elif __FreeBSD__ == 1		/* 1.1 defined it to be 1 */
4#define __FreeBSD_version 199405
5#else				/* 2.0 and higher define it to be 2 */
6#include <osreldate.h>		/* and this works */
7#endif
8#include <stdio.h>
9#include <unistd.h>
10
11int
12main(void) {
13	printf("Compilation release date: %d\n", __FreeBSD_version);
14#if __FreeBSD_version >= 199408
15	printf("Execution environment release date: %d\n", getosreldate());
16#else
17	printf("Execution environment release date: can't tell\n");
18#endif
19	return (0);
20}
21