So, since I don't write Zig I had to go look this up, to save anyone else the bother this is what Rust would call an 'as' cast or C programmers might think of as a value cast, it's going to try to make a value which has a similar meaning but of another type, which may be arbitrarily expensive. What people often want here is a transmute, Rust's core::mem::transmute which changes nothing about the bits except what those bits mean, since the bits didn't change and the machine only has bits anyway this is "free".