smx_action_t SIMIX_rdv_get_head(smx_rdv_t rdv);
void SIMIX_rdv_set_receiver(smx_rdv_t rdv, smx_process_t proc);
smx_process_t SIMIX_rdv_get_receiver(smx_rdv_t rdv);
-void SIMIX_comm_start(smx_action_t action);
smx_action_t SIMIX_comm_isend(smx_process_t src_proc, smx_rdv_t rdv,
double task_size, double rate,
void *src_buff, size_t src_buff_size,