iosfwd

It’s so you can declare, in your own headers, methods that rely on the declarations of iostream types without having to #include the iostream headers themselves, which are large, complex and slow to compile against. Here’s a simple example: // foo.h #include <iosfwd> void sucker(std::iostream& is);   // foo.cc #include <iostream> void sucker(std::iostream& is) { … Read more