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# CGFunctionCallbacks

A structure that contains callbacks needed by a `CGFunctionRef` object.

```
struct CGFunctionCallbacks
```

## Topics

### Initializers

[`init()`](/documentation/CoreGraphics/CGFunctionCallbacks/init())

[`init(version:evaluate:releaseInfo:)`](/documentation/CoreGraphics/CGFunctionCallbacks/init(version:evaluate:releaseInfo:))

### Instance Properties

[`evaluate`](/documentation/CoreGraphics/CGFunctionCallbacks/evaluate)

The callback that evaluates the function.

[`releaseInfo`](/documentation/CoreGraphics/CGFunctionCallbacks/releaseInfo)

If non-`NULL`,the callback used to release the `info` parameterpassed to [`init(info:domainDimension:domain:rangeDimension:range:callbacks:)`](/documentation/CoreGraphics/CGFunction/init(info:domainDimension:domain:rangeDimension:range:callbacks:)).

[`version`](/documentation/CoreGraphics/CGFunctionCallbacks/version)

The structure version number. For this structure,the version should be `0`.


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