#include <poll.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <unistd.h>

int main()
{
	struct pollfd info;

	info.fd = open("/proc/sys/kernel/hostname", O_RDONLY);
	info.events = 0;
	info.revents = 0;

	while (true) {
		int res = poll(&info, 1, -1);
		if (res > 0) {
			if (info.revents != 0) {
				char buffer[64];
				gethostname(buffer, sizeof(buffer));
				printf("Hostname has changed to: %s\n", buffer);
			}
		}
	}
}