Correct a few comments in threadqueue

include/ucore/threadqueue.h

@@ -153,6 +153,7 @@ int uc_thread_queue_init(struct uc_threadqueue *queue, unsigned int max_elements
  * Adds a message to a queue
  *
  * thread_queue_add adds a "message" to the specified queue. 
+ * If the queue is full, the call will block if the timeout agrument is non-NULL.
  * It is up to the application to manage the data and memory indicated by the
  * struct uc_threadmsg. 
  * The struct uc_threadmsg is assumed to be an intrusive pointer,
@@ -167,7 +168,8 @@ int uc_thread_queue_init(struct uc_threadqueue *queue, unsigned int max_elements
  * the front of the queue, i.e. it can be considered a "priority" message.
  *
  * @param queue Pointer to the queue on where the message should be added.
- * @param timeout timeout on how long to wait on a message, or NULL for no timeout
+ * @param timeout timeout on how long to wait until the queue has capacity to add the message
+ *        to the queue.
  * @param data the "message".
  * @return 0 on succes ENOMEM if out of memory EINVAL if queue is NULL, ETIMEDOUT if timeout occured or other
  * errno values if pthread functions failed.