As discussed, I'm not sure that example is valid - it's got many parameters and so it would never fit on one line.  For trivial getters like this, being concise is a good thing.  Either way, though, it's best not to reformat existing code unless it's definitely wrong.

(And technically, these almost certainly will be inline - the `inline` keyword is just a hint - the C compiler is smart enough to inline trivial functions defined in header files.)