Declarations for 2- and 3-argument GetMonData

[mrgriffin]

We definitely shouldn't name the functions GetMonData and GetMonData2, so this can't be merged without somebody coming up with a better suggestion.

Also, Rose on Discord suggested having something that wraps GetMonData for constant MON_DATA_* arguments, which might be nice (although the ones that are used both with GetMonData and GetMonData2 would end up being pretty ugly, so perhaps that's a nicer dream than reality).

I think this should match, but just to be sure I've opened a PR so that the CI system can tell me if it doesn't.

[tustin2121]

Might I suggest GetMonData and GetMonData_Param?
Or perhaps GetMonData_CopyOut or _Out, or something like that that specifies that the pointer added to the signature is an out parameter?

[GriffinRichards]

Is this really an improvement? It seems more likely that someone would search for the definition of e.g. GetMonData2 and get confused when they only find a declaration (assuming they're not sure what the alias attribute is doing). The current declarations are bad practice but I'd think that causes people less grief than this would.

[mrgriffin]

It's an improvement in the sense that it catches errors at compile time. Currently you can GetBoxMonData() and get some very interesting results. Also, alias is a bit confusing, but so is a function that seems to take either 2 or 3 arguments; that's not a thing that's common in C (besides the printf/scanf family of functions).

But to be clear, I mostly did this to see if it was possible, it's up to others to push for its inclusion or not.

[mrgriffin]

Reviving this in response to rh-hideout#3170.

Much less invasive than before, all calls (except one erroneous one in src/daycare.c) have stayed the same, and instead we use a macro to choose between GetMonData2 and GetMonData3 based on the number of arguments.

I think this change does achieve type-safety, e.g. the call in src/daycare.c was "wrong". It worked, because DaycareMon starts with a BoxPokemon member, and so C guarantees that the previous code worked. But I think it's nicer to pass the BoxPokemon pointer directly?

[GriffinRichards]

Could you put some similar comment in pokemon.c? I imagine some people will be confused when for example they can't find a definition of GetMonData in there, only GetMonData2 and GetMonData3.

[mrgriffin]

I've added some wording that I hope is useful :)

Feel free to squash this if you merge it.