Preprocessor Directives in 3.8

Are there predefined preprocessor directives to be used or do I have to define them myself? If I do have to define them myself, where or how can I do it?

I have a net standard library with shared code and I want to be able to distinguish between the platforms at some places.

I want different input processing code to be executed for Android (Touch) and Desktop (mouse / keyboard / game pad).

Can’t to that in netstandard libraries. Only in platform-specific projects.

How to distinguish platforms:

So if I have a shared Game1.cs in a net standard project I can’t for example find out if I am on Android and have to process touch input instead of mouse / keyboard / game pad input for desktop?

I tried with the code above and on Android the Platform is identified as Linux. But on Linux Desktop I would get the same result, so that will not help me to know if I need to process touch input or not.

No. You need to do it as I did in the link.