Abstract
- In Graphics
- Reduce the number of cpp files that get recompiled when you touch a header file.
- This happens by moving the
#include from the header file to the source file.
- The cpp file still gets recompiled when you touch the header file, but the circular dependency is broken.
Definition
- Not
#includeing in header files.
- Example:
class Ship* ship;.
- Instead, telling the compiler hey, I promise, there will be this class definition!
- This only works when referring to a pointer or reference
- When there is no need to construct
- Calling function requires
#include.
- Virtual functions are irrelevant with a forward declaration.
Benefits
- Compile time improvements
- Resolves circular dependency
#pragma once solves circular dependency but does not resolve the order dependency.
Rule of Thumb
- avoid including headers in headers.
- use pointers of a class.
- include inside cpp.