+ * Set the libsigrokdecode log callback to the specified function.
+ *
+ * @param cb Function pointer to the log callback function to use.
+ * Must not be NULL.
+ * @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 libsigrokdecode,
+ * and is never used or interpreted in any way. The pointer
+ * is allowed to be NULL if the caller doesn't need/want to
+ * pass any data.