# ThreadNotSupported

> Specifies that an evaluator does not support worker thread evaluation and should only be evaluated in the main thread. This could be the case if an evaluator is using non-tread safe Unity API (like AssetDatabase ).

## Definition

* **Type:** Field
* **Namespace:** [UnityEditor.Search](/engine/6000.7/script-reference/unityeditor/search.md)
* **Assembly:** UnityEditor

```csharp
ThreadNotSupported = 2
```

### Examples

```csharp
[Description("Returns asset paths corresponding to a list of instance ids")]
[SearchExpressionEvaluator("IdsToPaths", SearchExpressionEvaluationHints.ThreadNotSupported, SearchExpressionType.Iterable)]
public static IEnumerable<SearchItem> IdsToPath(SearchExpressionContext c)
{
    foreach (var idItem in c.args[0].Execute(c))
    {
        if (SearchExpression.TryConvertToULong(idItem, out var idNum))
        {
            var id = UnsafeUtility.As<ulong, EntityId>(ref idNum);
            var path = AssetDatabase.GetAssetPath(id);
            if (!string.IsNullOrEmpty(path))
            {
                yield return SearchExpression.CreateItem(path, c.ResolveAlias("asset path"));
            }
        }
    }
}
```