How are native Windows libraries (dll) realized on other OS like Android/iOS

Hi,

i haven't found a better discussion topic.
The System.dll which provides a lot of methods wich requires hardware access (like Date/Time, network, ...) works on Android/iOS/Windows/....
I don't know if it's the origin System.dll of window. When it is the origin i am asking me how this is realized for multiple OS. This is that i can have a better imagination about which error could occour.
The OS handle hardware acces on different way and there are also different adresses. So how is this realized?

kind regards