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# PetscTimeSubtract
Subtracts the current time (in seconds) from the value `v`. 
## Synopsis
```
#include <petsctime.h>
PetscErrorCode PetscTimeSubtract(PetscLogDouble *v)
```
Not Collective


## Input Parameter

- ***v -*** time counter



## Output Parameter

- ***v -*** time counter (`v` = `v` - current time)





## Notes
Since the PETSc libraries incorporate timing of phases and operations,
we do not always recommend using `PetscTimeSubtract()`.
The options database command  `-log_view` activates
PETSc library timing. See `PetscLogStageRegister()`, `PetscLogEventRegister()`, `PetscLogEventBegin()`, `PetscLogEventEnd()` for how to register
stages and events in application codes.


## See Also
 `PetscTime()`, `PetscTimeAdd()`, `PetscLogStageRegister()`, `PetscLogEventRegister()`, `PetscLogEventBegin()`, `PetscLogEventEnd()`

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/include/petsctime.h.html#PetscTimeSubtract">include/petsctime.h</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/include/petsctime.h)


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