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