+/* @brief MSG_mailbox_get_head - get the task at the head of a mailbox.
+ * Returns the task at the head of the mailbox. This function does not remove the task from the mailbox.
+ * @param mailbox The mailbox concerned by the operation.
+ * @return The task at the head of the mailbox.
+ */
+XBT_PUBLIC(msg_task_t) MSG_mailbox_get_head(msg_mailbox_t mailbox);
+
+/* @brief MSG_mailbox_get_count_host_waiting_tasks
+ * Return the number of tasks waiting to be received in a mailbox and sent by a host.
+ * @param mailbox The mailbox concerned by the operation.
+ * @param host The host containing the processes that sended the tasks.
+ * @return The number of tasks in the mailbox specified by the parameter mailbox and sended by all the
+ * processes located on the host specified by the parameter host.
+ */
+XBT_PUBLIC(int) MSG_mailbox_get_count_host_waiting_tasks(msg_mailbox_t mailbox, msg_host_t host);
+XBT_PUBLIC(msg_error_t) MSG_mailbox_get_task_ext(msg_mailbox_t mailbox, msg_task_t * task, msg_host_t host,
+ double timeout);
+XBT_PUBLIC(msg_error_t) MSG_mailbox_get_task_ext_bounded(msg_mailbox_t mailbox, msg_task_t *task, msg_host_t host,
+ double timeout, double rate);
+XBT_PUBLIC(msg_error_t) MSG_mailbox_put_with_timeout(msg_mailbox_t mailbox, msg_task_t task, double timeout);
+