+int Win::compare_and_swap(void *origin_addr, void *compare_addr,
+ void *result_addr, MPI_Datatype datatype, int target_rank,
+ MPI_Aint target_disp){
+ //get sender pointer
+ MPI_Win send_win = connected_wins_[target_rank];
+
+ if(opened_==0){//check that post/start has been done
+ // no fence or start .. lock ok ?
+ int locked=0;
+ for(auto it : send_win->lockers_)
+ if (it == comm_->rank())
+ locked = 1;
+ if(locked != 1)
+ return MPI_ERR_WIN;
+ }
+
+ XBT_DEBUG("Entering MPI_Compare_and_swap with %d", target_rank);
+ MPI_Request req;
+ xbt_mutex_acquire(send_win->atomic_mut_);
+ get(result_addr, 1, datatype, target_rank,
+ target_disp, 1, datatype, &req);
+ if (req != MPI_REQUEST_NULL)
+ Request::wait(&req, MPI_STATUS_IGNORE);
+ if(! memcmp (result_addr, compare_addr, datatype->get_extent() )){
+ put(origin_addr, 1, datatype, target_rank,
+ target_disp, 1, datatype);
+ }
+ xbt_mutex_release(send_win->atomic_mut_);
+ return MPI_SUCCESS;
+}
+