Let's say I have a class with a virtual function with one argument and two different implementations of this virtual function. The first implementation uses the argument while the second does not. The second case will produce a compilation warning. There are two ways I can think of to suppress the warning.

1. Using an anonymous parameter.
2. Using the [[maybe_unused]] annotation.

What is considered "best practice" between the two?

Thank you in advance for your answers.

CodePudding user response：

The most authoritative source we have for "best practice" in C is the C Core Guidelines. And on the topic of unused arguments, they have this to say

F.9: Unused parameters should be unnamed

...

If parameters are conditionally unused, declare them with the [[maybe_unused]] attribute.

So the C Core Guidelines recommend leaving the parameter unnamed if it's never used at all. [[maybe_unused]], by this rule, should only be applied if the parameter is unused in some situations, such as inside an #ifdef or (more modern) inside an if constexpr.