# fsVarsOVarSet<no value>
The **fsVarsOVarSet** function can be used to set the value of a specific `OVar`.

 

##### Syntax

``` wasm
FsVarError fsVarsOVarSet(
    FsOVarId oVarId,
    FsUnitId unitId,
    double value,
    FsObjectId target
);
```

 

##### Parameters

<table><thead><tr class="header"><th>Parameters</th><th>Description</th></tr></thead><tbody><tr class="odd"><td><code>oVarId</code></td><td><p>The ID of an <code>OVar</code> (found using <code>fsVarsGetOVarId</code> or <code>fsVarsRegisterOVar</code>).</p></td></tr><tr class="even"><td><code>unitId</code></td><td>The ID of a unit (found using <code>fsVarsGetUnitId</code>).</td></tr><tr class="odd"><td><code>value</code></td><td>The new value of the variable.</td></tr><tr class="even"><td><code>target</code></td><td><p>The ID of the object on which the variable is being set.</p></td></tr></tbody></table>

 

##### Return Values

The function returns `FsVarError`, where 0 means there is no error.

 

##### Example

``` wasm
FsUnitId unitId = fsVarsGetUnitId("DEGREES");
FsOVarId oVarId = fsVarsRegisterOVar("Toto", "LIGHTING:EMISSIVE");
double value = 8;
if (fsVarsOVarSet(oVarId, unitId, value) == FS_VAR_ERROR_NONE)
{
    // valid
}
else
{
    // error
}
```