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 9 int main(void) { 10 extern int getosreldate(void); 11 printf("Compilation release date: %d\n", __FreeBSD_version); 12 #if __FreeBSD_version >= 199408 13 printf("Execution environment release date: %d\n", getosreldate()); 14 #else 15 printf("Execution environment release date: can't tell\n"); 16 #endif 17 } 18