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# CGError

A uniform type for result codes returned by functions in Core Graphics.

```
enum CGError
```

## Topics

### Constants

[`CGError.cannotComplete`](/documentation/CoreGraphics/CGError/cannotComplete)

The requested operation is inappropriate for the parameters passed in, or the current system state.

[`CGError.failure`](/documentation/CoreGraphics/CGError/failure)

A general failure occurred.

[`CGError.illegalArgument`](/documentation/CoreGraphics/CGError/illegalArgument)

One or more of the parameters passed to a function are invalid. Check for `NULL` pointers.

[`CGError.invalidConnection`](/documentation/CoreGraphics/CGError/invalidConnection)

The parameter representing a connection to the window server is invalid.

[`CGError.invalidContext`](/documentation/CoreGraphics/CGError/invalidContext)

The `CPSProcessSerNum` or context identifier parameter is not valid.

[`CGError.invalidOperation`](/documentation/CoreGraphics/CGError/invalidOperation)

The requested operation is not valid for the parameters passed in, or the current system state.

[`CGError.noneAvailable`](/documentation/CoreGraphics/CGError/noneAvailable)

The requested operation could not be completed as the indicated resources were not found.

[`CGError.notImplemented`](/documentation/CoreGraphics/CGError/notImplemented)

Return value from obsolete function stubs present for binary compatibility, but not typically called.

[`CGError.rangeCheck`](/documentation/CoreGraphics/CGError/rangeCheck)

A parameter passed in has a value that is inappropriate, or which does not map to a useful operation or value.

[`CGError.success`](/documentation/CoreGraphics/CGError/success)

The requested operation was completed successfully.

[`CGError.typeCheck`](/documentation/CoreGraphics/CGError/typeCheck)

A data type or token was encountered that did not match the expected type or token.

## See Also

  [Quartz 2D Programming Guide](https://developer.apple.com/library/archive/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/Introduction/Introduction.html#//apple_ref/doc/uid/TP30001066)


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