iOS 10 doesn't print NSLogs
It could be that you added the property "OS_ACTIVITY_MODE": "disable" in the Scheme environment variables (to hide OS output from the simulator) and forgot about it, and now are running on a real device.
In Xcode 8:
Product -> Scheme -> Edit Scheme -> Run -> Arguments -> Environment Variables
Only add OS_ACTIVITY_MODE
and check it(Don't add a value)
Summary: This is a bug of Xcode 8 + iOS10, we can solve it in this way:
When using the simulator, add the Name "OS_ACTIVITY_MODE" and the Value "disable" and check it.
When on a real device, only add "OS_ACTIVITY_MODE" and check it(Don't add the Value). You will see the NSLog in the Xcode8 Console.
the NSlog or print actually is executed but is hidden among lots of other console debug outputs to solve this issueOpen Xcode8:
Product -> Scheme -> Edit Scheme -> Run -> Arguments -> Environment Variables
add "OS_ACTIVITY_MODE" and set the Value to "disable" and check it.
click close
xcode9
add "OS_ACTIVITY_MODE" and set the Value to "default" and check it.