Is there a way to check for available space on iOS? Before creating a local backup, I want to make sure there is room for it on the device.
Nope, just a way to capture the failure if it fails to create the file.
Not sure what error it returns, but you could do a generic error check, like:
Set Error Capture - On
Set Variable [ $e ; get(lasterror) ]
if [ $e <> 0 ]
Show Custom Dialog [ "error message: " & $e ]
Once you figured out the error code, you could make a more elegant action.
Retrieving data ...