# SNESLineSearchSetDefaultMonitor
Turns on/off printing useful information and debugging output about the line search. 
## Synopsis
```
#include "petscsnes.h" 
PetscErrorCode SNESLineSearchSetDefaultMonitor(SNESLineSearch linesearch, PetscViewer viewer)
```
Logically Collective on linesearch


## Input Parameters

- ***linesearch -*** the linesearch object
- ***viewer -*** an `PETSCVIEWERASCII` `PetscViewer` or NULL to turn off monitor



## Options Database Key

- ***-snes_linesearch_monitor [:filename] -*** enables the monitor





## Developer Note
This monitor is implemented differently than the other line search monitors that are set with
`SNESLineSearchMonitorSet()` since it is called in many locations of the line search routines to display aspects of the
line search that are not visible to the other monitors.


## See Also
 `SNESLineSearch`, `PETSCVIEWERASCII`, `SNESGetLineSearch()`, `SNESLineSearchGetDefaultMonitor()`, `PetscViewer`, `SNESLineSearchSetMonitor()`,
`SNESLineSearchMonitorSetFromOptions()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/linesearch/interface/linesearch.c.html#SNESLineSearchSetDefaultMonitor">src/snes/linesearch/interface/linesearch.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/snes/linesearch/interface/linesearch.c)


[Index of all SNES routines](index.md)  
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[Index of all manual pages](/docs/manualpages/singleindex.md)  
