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# PetscViewerSAWsOpen
Opens an SAWs `PetscViewer`. 
## Synopsis
```
#include "petscsys.h"  */
PetscErrorCode PetscViewerSAWsOpen(MPI_Comm comm, PetscViewer *lab)
```
Collective; No Fortran Support


## Input Parameter

- ***comm -*** the MPI communicator



## Output Parameter

- ***lab -*** the `PetscViewer`



## Options Database Keys

- ***-saws_port <port number> -*** port number where you are running SAWs client
- ***-xxx_view saws -*** publish the object xxx
- ***-xxx_saws_block -*** blocks the program at the end of a critical point (for `KSP` and `SNES` it is the end of a solve) until
the user unblocks the problem with an external tool that access the object with SAWS





## Notes
Unlike other viewers that only access the object being viewed on the call to `XXXView`(object,viewer) the SAWs viewer allows
one to view the object asynchronously as the program continues to run. One can remove SAWs access to the object with a call to
`PetscObjectSAWsViewOff()`.

Information about the SAWs is available via https://bitbucket.org/saws/saws


## See Also
 [](sec_viewers), `PetscViewerDestroy()`, `PetscViewerStringSPrintf()`, `PETSC_VIEWER_SAWS_()`, `PetscObjectSAWsBlock()`,
`PetscObjectSAWsViewOff()`, `PetscObjectSAWsTakeAccess()`, `PetscObjectSAWsGrantAccess()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/sys/classes/viewer/impls/ams/amsopen.c.html#PetscViewerSAWsOpen">src/sys/classes/viewer/impls/ams/amsopen.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/sys/classes/viewer/impls/ams/amsopen.c)


[Index of all Viewer routines](index.md)  
[Table of Contents for all manual pages](/manualpages/index.md)  
[Index of all manual pages](/manualpages/singleindex.md)