# PetscSFWindowSyncType
Type of synchronization for `PETSCSFWINDOW` 
## Synopsis
```
typedef enum {
  PETSCSF_WINDOW_SYNC_FENCE,
  PETSCSF_WINDOW_SYNC_LOCK,
  PETSCSF_WINDOW_SYNC_ACTIVE
} PetscSFWindowSyncType;
```
```none
`PETSCSF_WINDOW_SYNC_FENCE` - simplest model, synchronizing across communicator
```
```none
`PETSCSF_WINDOW_SYNC_LOCK` - passive model, less synchronous, requires less setup than PETSCSF_WINDOW_SYNC_ACTIVE, but may require more handshakes
```
```none
`PETSCSF_WINDOW_SYNC_ACTIVE` - active model, provides most information to MPI implementation, needs to construct 2-way process groups (more setup than PETSCSF_WINDOW_SYNC_LOCK)
```




## See Also
 `PetscSFWindowSetSyncType()`, `PetscSFWindowGetSyncType()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/include/petscsf.h.html#PetscSFWindowSyncType">include/petscsf.h</A>


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