Systematic declaration of thread variables

[Gintaras]

I wonder whether there exists a way to declare once in one specific function these variables and afterwards to "call" somehow this specific function in the functions which make use of these thread variables

Does not exist in QM.

I can define a type variable and use it in functions. However, I am not sure whether this is the best way to do it.

Yes, it is the best way. Or use a class, it is similar.