Alternative to FindWindow on Mac?

Question

C++ / C#

Is there any alternative to FindWindow (a function that returns a pointer to a window by its title) from the Mac's WinAPI? I'm trying to figure out how difficult it is to transfer a couple of methods to a Mac, but I've never worked with it and a light Google showed that there is some kind of nonsense (like the whole OS, in general) with this.
Subject - is it possible to get a window\pointer to it\immediately a screenshot of a window on a Mac from C++?