---
title: "semantic(forSymbol:)"
framework: scenekit
role: symbol
role_heading: Instance Method
path: "scenekit/scnprogram/semantic(forsymbol:)"
---

# semantic(forSymbol:)

Returns the SceneKit semantic identifiers associated with the specified GLSL vertex attribute or uniform variable.

## Declaration

```swift
func semantic(forSymbol symbol: String) -> String?
```

## Parameters

- `symbol`: The name declared in the program’s GLSL source code for a vertex attribute or uniform variable semantic.

## Return Value

Return Value A SceneKit semantic identifier. See Geometry Semantic Identifiers and Rendering Transform Keys for possible values.

## See Also

### Mapping GLSL Symbols to SceneKit Semantics

- [setSemantic(_:forSymbol:options:)](scenekit/scnprogram/setsemantic(_:forsymbol:options:).md)
- [SCNProgramMappingChannelKey](scenekit/scnprogrammappingchannelkey.md)
- [SCNModelTransform](scenekit/scnmodeltransform.md)
- [SCNModelViewProjectionTransform](scenekit/scnmodelviewprojectiontransform.md)
- [SCNModelViewTransform](scenekit/scnmodelviewtransform.md)
- [SCNNormalTransform](scenekit/scnnormaltransform.md)
- [SCNProjectionTransform](scenekit/scnprojectiontransform.md)
- [SCNViewTransform](scenekit/scnviewtransform.md)