watch.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <linux/inotify.h>

#define EVENT_SIZE (sizeof (struct inotify_event))
#define EVENT_BUF_LEN (1024 * (EVENT_SIZE + 16))

int main()
{
	int fd = inotify_init();
	if (fd < 0) {
		perror("inotify_init");
	}

	int wd = inotify_add_watch(fd, "hello.txt", IN_ACCESS | IN_ATTRIB | IN_CLOSE_WRITE | IN_CLOSE_NOWRITE | IN_CREATE | IN_DELETE | IN_DELETE_SELF | IN_MODIFY | IN_MOVE_SELF | IN_MOVED_FROM | IN_MOVED_TO | IN_OPEN);

	for (;;) {
		int length, i = 0;
		char buffer[EVENT_BUF_LEN];

		length = read(fd, buffer, EVENT_BUF_LEN);
		if (length < 0) {
			perror("read");
		}

		while (i < length) {
			struct inotify_event *event = (struct inotify_event *) &buffer[i];
			if (event->mask & IN_ACCESS) printf("IN_ACCESS ");
			if (event->mask & IN_ATTRIB) printf("IN_ATTRIB ");
			if (event->mask & IN_CLOSE_WRITE) printf("IN_CLOSE_WRITE ");
			if (event->mask & IN_CLOSE_NOWRITE) printf("IN_CLOSE_NOWRITE ");
			if (event->mask & IN_CREATE) printf("IN_CREATE ");
			if (event->mask & IN_DELETE) printf("IN_DELETE ");
			if (event->mask & IN_DELETE_SELF) printf("IN_DELETE_SELF ");
			if (event->mask & IN_MODIFY) printf("IN_MODIFY ");
			if (event->mask & IN_MOVE_SELF) printf("IN_MOVE_SELF ");
			if (event->mask & IN_MOVED_FROM) printf("IN_MOVED_FROM ");
			if (event->mask & IN_MOVED_TO) printf("IN_MOVED_TO ");
			if (event->mask & IN_OPEN) printf("IN_OPEN ");
			printf("\n");

			i += EVENT_SIZE + event->len;
		}

		printf("--------\n");
	}

	inotify_rm_watch(fd, wd);
	close(fd);
}