> I know for a fact that (modulo people doing incredibly stupid things with macros), that this is simple arithmetic addition. I don't know that for a fact in C++ - because of operator overloading.
The only way to know for a fact what happens in either C or C++ is to know the types of A & B, which you (seemingly intentionally) omitted.
But if A & B are the types that can be added in C, then it's going to be literally identical in C++ with no chance of operator overloading. If A & B are not types that can be added in C, then you would see an add() function called instead and you'd be right back to not knowing what it does.
Yes, I am intentionally not looking at the types, because that's something that might not be incredibly apparent in C++ (or C).
We're violently agreeing at this point. Yes, in C, this problem does not exist, because operator overloading does not exist.
In C++, what `A+B` does is ambiguous without knowing 1) what are the types of A and B, and 2) what are all the possible `operator+` overloads that exist which may operate on A and B. It's a hidden complexity which doesn't make potentially expensive operations apparent, and kernels and VMs hate that kind of thing.
> because that's something that might not be incredibly apparent in C++ (or C).
Yes, it is. Extremely so.
> Yes, in C, this problem does not exist, because operator overloading does not exist.
Except it totally still does because you never know what function add does for random types. It's literally the same exact thing. Function calls might be expensive and they might not be.
> It's a hidden complexity which doesn't make potentially expensive operations apparent, and kernels and VMs hate that kind of thing.
No, it really isn't. The add overload operator is never non-obvious, and never actually does memory allocation, file io, or any of that other nonsense.
Can you be intentionally stupid about it? Yes, sure. Is that an actual concern that anyone working on a VM or kernel should have? No, not in the slightest. Completely nonsense.
The only way to know for a fact what happens in either C or C++ is to know the types of A & B, which you (seemingly intentionally) omitted.
But if A & B are the types that can be added in C, then it's going to be literally identical in C++ with no chance of operator overloading. If A & B are not types that can be added in C, then you would see an add() function called instead and you'd be right back to not knowing what it does.