C++ conventions regarding passing objects (pointer vs reference)

Question

I'd like to work out conventions on passing parameters to functions/methods. I know it's a common issue and it has been answered many times, but I searched a lot and found nothing that fully satisfies me.

Passing by value is obvious and I won't mention this. What I came up with is:

1. Passing by non-const reference means, that object is MODIFIED
2. Passing by const reference means, that object is USED
3. Passing by pointer means, that a reference to object is going to be STORED. Whether ownership is passed or not will depend on the context.

It seems to be consistent, but when I want to pick heap-allocated object and pass it to 2. case parameter, it'd look like this:

void use(const Object &object) { ... }

//...

Object *obj = getOrCreateObject();
use(*obj);

or

Object &obj = *getOrCreateObject();
use(obj);

Both look weird to me. What would you advise?

PS I know that one should avoid raw pointers and use smart instead (easier memory managment and expressiveness in ownership) and it can be the next step in refactoring the project I work on.

Answer 1

You can use these conventions if you like. But keep in mind that you cannot assume conventions when dealing with code written by other people. You also cannot assume that people reading your code are aware of your conventions. You should document an interface with comments when it might be ambiguous.

Passing by pointer means, that object is going to be STORED. Who's its owner will depend on the context.

I can think of only one context where the ownership of a pointer argument should transfer to the callee: Constructor of a smart pointer.

Besides possible intention of storing, a pointer argument can alternatively have the same meaning as a reference argument, with the addition that the argument is optional. You typically cannot represent an optional argument with a reference since they cannot be null - although with custom types you could use a reference to a sentinel value.

Both look weird to me. What would you advise?

Neither look weird to me, so my advise is to get accustomed.