# PetscMemoryGetMaximumUsage
Returns the maximum resident set size (memory used) for the program since it started (the high water mark). 
## Synopsis
```
#include "petscsys.h" 
PetscErrorCode PetscMemoryGetMaximumUsage(PetscLogDouble *mem)
```
Not Collective


## Output Parameter

- ***mem -*** memory usage in bytes



## Options Database Key

- ***-memory_view -*** Print memory usage at end of run
- ***-log_view_memory -*** Print memory information per event
- ***-malloc_log -*** Activate logging of memory usage





## Note
The memory usage reported here includes all Fortran arrays
(that may be used in application-defined sections of code).
This routine thus provides a more complete picture of memory
usage than `PetscMallocGetCurrentUsage()` for codes that employ Fortran with
hardwired arrays.


## See Also
 `PetscMallocGetMaximumUsage()`, `PetscMemoryGetCurrentUsage()`, `PetscMallocGetCurrentUsage()`,
`PetscMemorySetGetMaximumUsage()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/sys/memory/mem.c.html#PetscMemoryGetMaximumUsage">src/sys/memory/mem.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/sys/memory/mem.c)


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