Back to the example

 1   def read_configuration(filename)
 2     f = File.open(filename)
 3     host = f.gets
 4     port = f.gets.to_i
 5     f.close
 6     return host, port
 7   end

Question: Is this exception-safe?
If an exception is raised an exception, then:
The state is consistent
No resources are leaked
Answer: Yes, but...