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# isActive

A Boolean that indicates whether the compiled function uses the argument.

```
var isActive: Bool { get }
```

## Discussion

When you create the [`MTLFunction`](/documentation/Metal/MTLFunction) object, Metal statically determines whether the function uses the argument. If <doc://com.apple.documentation/documentation/Swift/true>, you need to provide a value for this argument when you encode a command that calls this function. If <doc://com.apple.documentation/documentation/Swift/false>, the function doesn’t use the argument, and you can ignore it.

---

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