:orphan:
# PetscOptionsReal
Gets the `PetscReal` value for a particular option in the database. 
## Synopsis
```
#include "petscsys.h"
PetscErrorCode  PetscOptionsReal(const char opt[],const char text[],const char man[],PetscReal currentvalue,PetscReal *value,PetscBool  *set)
```
Logically Collective on the communicator passed in `PetscOptionsBegin()`


## Input Parameters

- ***opt -*** option name
- ***text -*** short string that describes the option
- ***man -*** manual page with additional information on option
- ***currentvalue -*** the current value; caller is responsible for setting this value correctly. Normally this is done with either


```none
                 PetscOptionsReal(..., obj->value,&obj->value,...) or
                 value = defaultvalue
                 PetscOptionsReal(..., value,&value,&flg);
                 if (flg) {
```



## Output Parameters

- ***value -*** the value to return
- ***flg -*** `PETSC_TRUE` if found, else `PETSC_FALSE`





## Notes
If the user does not supply the option at all `value` is NOT changed. Thus
you should ALWAYS initialize `value` if you access it without first checking if `flg` is `PETSC_TRUE`.

The `currentvalue` passed into this routine does not get transferred to the output `value` variable automatically.

Must be between a `PetscOptionsBegin()` and a `PetscOptionsEnd()`


## See Also
 `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`, `PetscOptionsGetInt()`,
`PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsGetBool()`,
`PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`, `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/aoptions.c.html#PetscOptionsReal">src/sys/objects/aoptions.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/plex/tutorials/ex13.c.html">src/dm/impls/plex/tutorials/ex13.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/plex/tutorials/ex9.c.html">src/dm/impls/plex/tutorials/ex9.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex29.c.html">src/ksp/ksp/tutorials/ex29.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex35.cxx.html">src/ksp/ksp/tutorials/ex35.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex36.cxx.html">src/ksp/ksp/tutorials/ex36.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex56.c.html">src/ksp/ksp/tutorials/ex56.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex73.c.html">src/ksp/ksp/tutorials/ex73.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex74.c.html">src/ksp/ksp/tutorials/ex74.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex15.c.html">src/snes/tutorials/ex15.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex31.c.html">src/snes/tutorials/ex31.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex46.c.html">src/snes/tutorials/ex46.c</A><BR>


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


[Index of all Sys routines](index.md)  
[Table of Contents for all manual pages](/manualpages/index.md)  
[Index of all manual pages](/manualpages/singleindex.md)