XBT_PUBLIC(MSG_error_t) MSG_task_cancel(m_task_t task);
XBT_PUBLIC(MSG_error_t) MSG_task_destroy(m_task_t task);
XBT_PUBLIC(void) MSG_task_ref(m_task_t t);
-XBT_PUBLIC(int) MSG_task_has_data(m_task_t t);
XBT_PUBLIC(MSG_error_t) MSG_task_get(m_task_t * task, m_channel_t channel);
XBT_PUBLIC(MSG_error_t) MSG_task_get_with_timeout(m_task_t * task,