# lookup_var<no value>
The **lookup\_var** function updates the contents of a token variable.

 

##### Syntax

``` wasm
void lookup_var(
    PMODULE_VAR  module_var
    );
```

 

##### Members

{{< table-wrapper >}}

| Parameters   | Description                                                                                                       |
|--------------|-------------------------------------------------------------------------------------------------------------------|
| `module_var` | Pointer to a [MODULE\_VAR](../token-vars/token-variables/) structure, containing the token variable to update. |

{{< /table-wrapper >}}


 

##### Return Values

This function does not return a value.

 

##### Example

``` wasm
MODULE_VAR gs_var = {VOR1_GS_FLAG}; 
    Void update_routine() 
    { 
        lookup_var(&gs_var); 
        if(gs_var.var_value.n == 0) 
        { 
            HIDE_IMAGE((&gs_slider)); 
            HIDE_IMAGE((&gs_background)); 
        } 
        else 
        { 
            SHOW_IMAGE((&gs_slider)); 
            SHOW_IMAGE((&gs_background)); 
        } 
    'Include other update code
    }
```

 

##### Remarks

Before using the contents of a module variable, you must call the `lookup_var` function.