# PetscViewerBinaryGetFlowControl
Returns how many messages are allowed to outstanding at the same time during parallel IO reads/writes 
## Synopsis
```
#include "petscviewer.h"   
PetscErrorCode PetscViewerBinaryGetFlowControl(PetscViewer viewer, PetscInt *fc)
```
Not Collective


## Input Parameter

- ***viewer -*** `PetscViewer` context, obtained from `PetscViewerBinaryOpen()`



## Output Parameter

- ***fc -*** the number of messages





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

## Level
advanced

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

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/sys/classes/viewer/impls/binary/binv.c.html#PetscViewerBinaryGetFlowControl_Binary">PetscViewerBinaryGetFlowControl_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](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
