# PetscOptionsGetReal
Gets the double precision value for a particular option in the database. 
## Synopsis
```
#include "petscsys.h"   
PetscErrorCode PetscOptionsGetReal(PetscOptions options, const char pre[], const char name[], PetscReal *dvalue, PetscBool *set)
```
Not Collective


## Input Parameters

- ***options -*** options database, use NULL for default global database
- ***pre -*** string to prepend to each name or NULL
- ***name -*** the option one is seeking



## Output Parameters

- ***dvalue -*** the double value to return
- ***set -*** `PETSC_TRUE` if found, `PETSC_FALSE` if not found



## Note
If the user does not supply the option dvalue is NOT changed. Thus
you should ALWAYS initialize the ivalue if you access it without first checking if the set flag is true.




## See Also
 `PetscOptionsGetInt()`, `PetscOptionsHasName()`,
`PetscOptionsGetString()`, `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`,
`PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
`PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
`PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
`PetscOptionsFList()`, `PetscOptionsEList()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/sys/objects/options.c.html#PetscOptionsGetReal">src/sys/objects/options.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/sys/classes/random/tutorials/ex2.c.html">src/sys/classes/random/tutorials/ex2.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/plex/tutorials/ex10.c.html">src/dm/impls/plex/tutorials/ex10.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/stag/tutorials/ex6.c.html">src/dm/impls/stag/tutorials/ex6.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/tutorials/ex26.c.html">src/dm/tutorials/ex26.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex11.c.html">src/ksp/ksp/tutorials/ex11.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex11f.F90.html">src/ksp/ksp/tutorials/ex11f.F90.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex21.c.html">src/ksp/ksp/tutorials/ex21.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex42.c.html">src/ksp/ksp/tutorials/ex42.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex43.c.html">src/ksp/ksp/tutorials/ex43.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex54.c.html">src/ksp/ksp/tutorials/ex54.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex54f.F90.html">src/ksp/ksp/tutorials/ex54f.F90.html</A><BR>


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


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