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# PetscViewerBinaryGetUseMPIIO
Returns `PETSC_TRUE` if the binary viewer uses MPI-IO. 
## Synopsis
```
#include "petscviewer.h"   
PetscErrorCode PetscViewerBinaryGetUseMPIIO(PetscViewer viewer, PetscBool *use)
```
Not Collective


## Input Parameter

- ***viewer -*** `PetscViewer` context, obtained from `PetscViewerBinaryOpen()`; must be a `PETSCVIEWERBINARY`



## Output Parameter

- ***use -*** `PETSC_TRUE` if MPI-IO is being used





## Note
If MPI-IO is not available, this function will always return `PETSC_FALSE`


## See Also
 [](sec_viewers), `PETSCVIEWERBINARY`, `PetscViewerBinaryOpen()`, `PetscViewerBinaryGetInfoPointer()`, `PetscViewerBinarySetUseMPIIO()`, `PetscViewerBinaryGetMPIIOOffset()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/sys/classes/viewer/impls/binary/binv.c.html#PetscViewerBinaryGetUseMPIIO">src/sys/classes/viewer/impls/binary/binv.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/tutorials/ex15.c.html">src/dm/tutorials/ex15.c</A><BR>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/sys/classes/viewer/impls/binary/binv.c.html#PetscViewerBinaryGetUseMPIIO_Binary">PetscViewerBinaryGetUseMPIIO_Binary in src/sys/classes/viewer/impls/binary/binv.c</A><BR>


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