Possible Duplicate:
why is “error:&error” used here (objective-c)
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device
error:&error];
What does the & symbol mean in the above code?
It’s the address-of operator; it produces a pointer pointing to the referent. In this case,
erroris anNSError *;AVCaptureDeviceInput deviceInputWithDevice:error:takes an address to it and may modifyerrorthrough that pointer to indicate the error that occurred.