signal when cd is inserted in C

Is there a way to detect if a CD is inserted in C on Linux?

I tried it with an SIGIO Signal:

fd = open("/dev/cdrom", O_RDWR | O_NONBLOCK );
struct sigaction saio;  

saio.sa_handler = signal_handler_IO;
saio.sa_flags = 0;
saio.sa_restorer = NULL; 
sigaction(SIGIO,&saio,NULL);

fcntl(fd, F_SETFL, FNDELAY);
fcntl(fd, F_SETOWN, getpid());
fcntl(fd, F_SETFL,  O_ASYNC );

But the function "signal_handler_IO" is never called.

Is there a possibility doing it this way?