-void mpi_win_get_attr_(int* win, int* type_keyval, void* attribute_val, int* flag, int* ierr){
- *ierr = MPI_Win_get_attr(simgrid::smpi::Win::f2c(*win), *type_keyval, attribute_val, flag);
+void mpi_win_get_attr_(int* win, int* type_keyval, int* attribute_val, int* flag, int* ierr){
+ int* value = nullptr;
+ *ierr = MPI_Win_get_attr(simgrid::smpi::Win::f2c(*win), *type_keyval, &value, flag);
+ if (*flag == 1)
+ *attribute_val = *value;