On Thu, 2022-01-20 at 08:59 +0800, Hongyi Zhao wrote: > Maybe I didn't express my question clearly. I actually meant to say > if the following one are equivalent to obtain the exit code: > > $($?) and $$?
It's essentially impossible to talk about variables by themselves: the only way it makes sense to talk about them is by showing how they are used. If you show me a complete example makefile that uses those two different forms, I can tell you what it will do and how make will treat them. Of course, if you do that you can just run make yourself and see what happens without needing to ask :). However, the short answer is no, they are not even close to being equivalent.
