Hello,

I'm trying to query a NSError object returned from on an AVFoundation call by reference.
The ObjectiveC Definition is

• (instancetype)deviceInputWithDevice:(AVCaptureDevice *)device
  error:(NSError **)outError;

I tried many combinations and can't figure it out:

err = c_void_p()
print err
err1 = pointer(err)
print err1

A)
deviceInput2=ObjCClass('AVCaptureDeviceInput').deviceInputWithDevice_error_(self.inputDevice2, byref(err1) )
print err1
B)
deviceInput2=ObjCClass('AVCaptureDeviceInput').deviceInputWithDevice_error(self._inputDevice2, err1 )
print err1

What I get is
c_void_p(None)
<objc_util.LP_c_void_p object at 0x10762af48>

A) c_void_p(None)
B) <objc_util.LP_c_void_p object at 0x10762af48>

What is the right way to do this and to get the NSError in the end?

All examples I found just seem to ignore the NSError by using None.

Many thanks!

Thank you! Yes it does work!
On the 7 Plus I'm able to access all 4 cameras this way. This is what I get and it works perfect:

(
"<AVCaptureFigVideoDevice: 0x12db72c40 [Back Camera][com.apple.avfoundation.avcapturedevice.built-in_video:0]>",
"<AVCaptureFigVideoDevice: 0x12dbeb240 [Front Camera][com.apple.avfoundation.avcapturedevice.built-in_video:1]>",
"<AVCaptureFigVideoDevice: 0x12dbe1b20 [Back Telephoto Camera][com.apple.avfoundation.avcapturedevice.built-in_video:2]>",
"<AVCaptureFigVideoDevice: 0x12dbe6bf0 [Back iSight Duo Camera][com.apple.avfoundation.avcapturedevice.built-in_video:3]>"
)

Thank you for the quick response. session.devices() returns empty even there should be a list of devices.
Might be an issue how I call the new API.

I'm new to Pythonista and the way objc_util interacts. Currently I trying to query the dual cameras on an IPhone 7 Plus.
I'm using the new way to query cameras in OSX 10
This is where I got stuck:

from objc_util import *

AVCaptureDeviceDiscoverySession = ObjCClass('AVCaptureDeviceDiscoverySession')

session = AVCaptureDeviceDiscoverySession.discoverySessionWithDeviceTypes_mediaType_position_(['AVCaptureDeviceTypeBuiltInDuoCamera' , 'AVCaptureDeviceTypeBuiltInWideAngleCamera', 'AVCaptureDeviceTypeBuiltInTelephotoCamera'],ns('AVMediaTypeVideo'),ns('AVCaptureDevicePositionUnspecified'))

How to implement the following line in Pythonista?

NSArray<AVCaptureDevice *> *devices = session.devices;
session.devices contains when I look at it on an iPhone 7 Plus (IOS 10.1beta):

<objc_util.ObjCInstanceMethodProxy object at 0x10c1a7a20>
How to cast from here to the NSArray AVCaptureDevice??
.
Many thanks for any hints!