> There is a point, perhaps a little specious, that you put a module's data structures behind a typedef so the interface doesn't change if it changes from a sim

> There is a point, perhaps a little specious, that you put a module's data structures behind a typedef so the interface doesn't change if it changes from a simple data type to a struct. Probably doesn't happen too often. you could never do this in C. If it is a "value type" i.e. a non-pointer, then you cannot change the size of the value, without changing the ABI and the function decl.