Proceeds to be donated to New York disaster relief. This is the original GotW problem and solution substantially as posted to Usenet. Problem JG Question 1.
Forward declarations are very useful tools.
In this case, they don't work as the programmer expected. Forward declarations are very useful tools. In this case, they don't work as the programmer expected. Unfortunately, the answer is that there is no standard and portable way to do this. The iosfwd header does contain bona fide forward declarations.