I'm working with a source base written almost entirely in straight-c (nginx). It does, however, make use of rich high level programming techniques such as compile-time metaprogramming, and OOP - including run-time dispatch.

I want to draw ER diagrams, UML class diagrams and UML sequence diagrams. However to have a clean mapping between the two, consistent conventions must be applied. So, I am hopping someone has some references to material that establishes or applies such conventions to similar style c-code.