* @param cb_data Pointer to private data to be passed on. This can be used by
* the caller to pass arbitrary data to the log functions. This
* pointer is only stored or passed on by libsigrok, and is
* @param cb_data Pointer to private data to be passed on. This can be used by
* the caller to pass arbitrary data to the log functions. This
* pointer is only stored or passed on by libsigrok, and is