v4l2-ioctl.c的一些学习和整理

可以发现，这个宏用的很好，简洁易扩展，自己写代码可以学习下

#define IOCTL_INFO(_ioctl, _func, _debug, _flags)		\[_IOC_NR(_ioctl)] = {					\.ioctl = _ioctl,				\.flags = _flags,				\.name = #_ioctl,				\.func = _func,					\.debug = _debug,				\}

static const char *v4l2_memory_names[] = {[V4L2_MEMORY_MMAP]    = "mmap",[V4L2_MEMORY_USERPTR] = "userptr",[V4L2_MEMORY_OVERLAY] = "overlay",[V4L2_MEMORY_DMABUF] = "dmabuf",
};