:orphan:
# PetscViewerBinaryGetFlowControl
Returns how many messages are allowed to be 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
src/sys/classes/viewer/impls/binary/binv.c
## Implementations
PetscViewerBinaryGetFlowControl_Binary in src/sys/classes/viewer/impls/binary/binv.c
---
[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)