They are widely used in Google code, but only for debug logging and test diagnostics. The << and >> stream operators provide an API for formatted I/O that is easily learned, portable, reusable, and extensible • Stream formatting can be configured by mutating the state of the stream. Such mutations are persistent, so the behavior of your code can be affected by the entire previous history of the stream, unless state variables and behaviors through a registration system. • It is difficult to precisely control stream output, due to the above issues, the way code and data are mixed in streaming code, and the use of