1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE	/* needed to get the defines */
3 #include <fcntl.h>	/* in glibc 2.2 this has the needed
4 				   values defined */
5 #include <signal.h>
6 #include <stdio.h>
7 #include <unistd.h>
8 
9 static volatile int event_fd;
10 
11 static void handler(int sig, siginfo_t *si, void *data)
12 {
13 	event_fd = si->si_fd;
14 }
15 
16 int main(void)
17 {
18 	struct sigaction act;
19 	int fd;
20 
21 	act.sa_sigaction = handler;
22 	sigemptyset(&act.sa_mask);
23 	act.sa_flags = SA_SIGINFO;
24 	sigaction(SIGRTMIN + 1, &act, NULL);
25 
26 	fd = open(".", O_RDONLY);
27 	fcntl(fd, F_SETSIG, SIGRTMIN + 1);
28 	fcntl(fd, F_NOTIFY, DN_MODIFY|DN_CREATE|DN_MULTISHOT);
29 	/* we will now be notified if any of the files
30 	   in "." is modified or new files are created */
31 	while (1) {
32 		pause();
33 		printf("Got event on fd=%d\n", event_fd);
34 	}
35 }
36