kqtest.c

#include <sys/types.h>
#include <sys/event.h>
#include <sys/time.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int
main(void)
{
    int f, kq, nev;
    struct kevent change;
    struct kevent event;

    kq = kqueue();
    if (kq == -1) {
        perror("kqueue");
    }

    f = open("/tmp/foo", O_RDONLY);
    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 EXIT_SUCCESS;
}