gistfile1.h

unsigned char
is_keyboard(const char *file)
{
    int     fd;
    uint8_t bitmask;

    fd = open(file, O_RDONLY);

    if (fd < 0) {
        return(0);
    }

    if (ioctl(fd, EVIOCGBIT(0, EV_MAX), &bitmask) < 0) {
        return(0);
    }

    /* make sure that the device supports EV_SYN and EV_KEY */
    if (!(bitmask & (1 << EV_SYN))) {
        return(0);
    }

    if (!(bitmask & (1 << EV_KEY))) {
        return(0);
    }

    /* make sure the device does not support EV_REL */
    if ((bitmask & (1 << EV_REL))) {
        return(0);
    }

    /* make sure the device do not support EV_ABS */
    if ((bitmask & (1 << EV_ABS))) {
        return(0);
    }

    return(1);
}