* is called. Once the continuation is called, the message is no longer in the
* queue.
*
- * If the send function was given no continuation, GMC_cancel should
- * NOT be called, since it's not possible to determine if the message has
- * already been sent.
- *
* @param q Handle to the queue.
*/
void
* @param cont Continuation called once message is sent. Can be NULL.
* @param cont_cls Closure for @c cont.
*
- * @return Handle to cancel the message before it's sent. NULL on error.
+ * @return Handle to cancel the message before it's sent.
+ * NULL on error or if @c cont is NULL.
* Invalid on @c cont call.
*/
struct MeshConnectionQueue *