:orphan:
# PetscOptionsGetScalar
Gets the scalar value for a particular option in the database. 
## Synopsis
```
#include "petscsys.h"   
PetscErrorCode PetscOptionsGetScalar(PetscOptions options, const char pre[], const char name[], PetscScalar *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, else `PETSC_FALSE`





## Usage
A complex number 2+3i must be specified with NO spaces


## 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#PetscOptionsGetScalar">src/sys/objects/options.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/stag/tutorials/ex1.c.html">src/dm/impls/stag/tutorials/ex1.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/stag/tutorials/ex4.c.html">src/dm/impls/stag/tutorials/ex4.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex25.c.html">src/ksp/ksp/tutorials/ex25.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex49.c.html">src/ksp/ksp/tutorials/ex49.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex58.c.html">src/snes/tutorials/ex58.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex21.c.html">src/ts/tutorials/ex21.c</A><BR>


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


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