---
title: "CGOpenGLDisplayMaskToDisplayID(_:)"
framework: coregraphics
role: symbol
role_heading: Function
path: "coregraphics/cgopengldisplaymasktodisplayid(_:)"
---

# CGOpenGLDisplayMaskToDisplayID(_:)

Maps an OpenGL display mask to a display ID.

## Declaration

```swift
func CGOpenGLDisplayMaskToDisplayID(_ mask: CGOpenGLDisplayMask) -> CGDirectDisplayID
```

## Parameters

- `mask`: The OpenGL display mask to be converted.

## Return Value

Return Value The display ID assigned to the specified display mask, or kCGNullDirectDisplay if no display matches the mask.

## Discussion

Discussion OpenGL sometimes identifies a display using a bitmask with one bit set. This function maps such a display mask to the corresponding display ID. If you pass in a mask with multiple bits set, this function returns a display ID matching one of these bits.

## See Also

### Functions

- [CGAcquireDisplayFadeReservation(_:_:)](coregraphics/cgacquiredisplayfadereservation(_:_:).md)
- [CGAssociateMouseAndMouseCursorPosition(_:)](coregraphics/cgassociatemouseandmousecursorposition(_:).md)
- [CGBeginDisplayConfiguration(_:)](coregraphics/cgbegindisplayconfiguration(_:).md)
- [CGCancelDisplayConfiguration(_:)](coregraphics/cgcanceldisplayconfiguration(_:).md)
- [CGCaptureAllDisplays()](coregraphics/cgcapturealldisplays().md)
- [CGCaptureAllDisplaysWithOptions(_:)](coregraphics/cgcapturealldisplayswithoptions(_:).md)
- [CGCompleteDisplayConfiguration(_:_:)](coregraphics/cgcompletedisplayconfiguration(_:_:).md)
- [CGConfigureDisplayFadeEffect(_:_:_:_:_:_:)](coregraphics/cgconfiguredisplayfadeeffect(_:_:_:_:_:_:).md)
- [CGConfigureDisplayMirrorOfDisplay(_:_:_:)](coregraphics/cgconfiguredisplaymirrorofdisplay(_:_:_:).md)
- [CGConfigureDisplayMode(_:_:_:)](coregraphics/cgconfiguredisplaymode(_:_:_:).md)
- [CGConfigureDisplayOrigin(_:_:_:_:)](coregraphics/cgconfiguredisplayorigin(_:_:_:_:).md)
- [CGConfigureDisplayStereoOperation(_:_:_:_:)](coregraphics/cgconfiguredisplaystereooperation(_:_:_:_:).md)
- [CGConfigureDisplayWithDisplayMode(_:_:_:_:)](coregraphics/cgconfiguredisplaywithdisplaymode(_:_:_:_:).md)
- [CGCursorIsDrawnInFramebuffer()](coregraphics/cgcursorisdrawninframebuffer().md)
- [CGCursorIsVisible()](coregraphics/cgcursorisvisible().md)