/* watch for file events using BSD kqueue */#include <sys/types.h>#include <sys/event.h>#include <sys/time.h>  #include <err.h>#include <fcntl.h>#include <stdio.h>#include <stdlib.h> #include <unistd.h> intmain(int argc, char *argv[]){	int f, kq, nev;	struct kevent change;	struct kevent event; 	if (argc < 2)		exit(1); 	kq = kqueue();	if (kq == -1)		errx(1, "kqueue"); 	f = open(argv[1], O_RDWR);	if (f == -1)		perror("open"); 	EV_SET(&change, f, EVFILT_VNODE,			EV_ADD | EV_ENABLE | EV_ONESHOT,			NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_ATTRIB,			0, 0); 	for (;;) {		nev = kevent(kq, &change, 1, &event, 1, NULL);		if (nev == -1)			perror("kevent");		else if (nev > 0) {			if (event.fflags & NOTE_DELETE) {				printf("File deleted\n");				break;			}			if (event.fflags & NOTE_EXTEND ||				event.fflags & NOTE_WRITE)				printf("File modified\n");			if (event.fflags & NOTE_ATTRIB)				printf("File attributes modified\n");		}	} 	close(kq);	close(f);	return 0;}