> and I'm calling it here: > > len = ioctl(cd, 0); > perror("ioctl"); > > but when runnig it says: > > ioctl: Inappropriate ioctl for device > > where's the problem? You should only call perror if ioctl returned -1. Try: len = ioctl(cd, 0); if (len == -1) { perror("ioctl"); }