#include <sys/socket.h>
#include <stdio.h>

int main(void) { 
	int s = socket(PF_UNIX, SOCK_STREAM, 0);
	if (s < 0)
		perror("socket");

	struct sockaddr sock;
	size_t size = sizeof(sock);

	if (getsockname(s, &sock, &size) < 0)
		perror("getsockname");

	printf("%d\n", sock.sa_family);

	return 0;
}