Some log libraries allow user configuration of logging. Some configurations can be as mundane as altering logging levels when debugging; other configurations co

Some log libraries allow user configuration of logging. Some configurations can be as mundane as altering logging levels when debugging; other configurations could redirect the logs away from text files to something that preserves semantics. But, depending on what your program is doing, printf/whatever can be "good enough." Coming from the C# world, one of the nice things about log4net is that it has a standard exception formatter, and callbacks whenever anything logs to error. This makes it easier to log unexpected errors and phone home when they happen.