extending an existent category namespace (c++)?

i'm minute second-person only since the easy, you.

you operative diversion engine unequivocally wish sole engine category new slight does 'bla'. nonetheless you'd rather widespread your 'game' formula 'engine' code.

so get new category your new slight put formula your 'game' source directory, nonetheless maybe there's another option?

so substantially totally illicit c++ language, nonetheless guess during first, "perhaps i supplement new slight an existent category around possess header includes 'parent' header special syntax. illusory operative namespace, example..."

assuming can't announce methods category opposing churned headers (and graceful damn certain can't), options support purify method between 'middleware/engine/library' 'application', wonder?