> That's not exactly what Go does, as you can return much more information and it's almost always clear what's an error and what isn't (there are a few exceptions, such as strings.Index() returning -1).

Yes it is exactly what Go does. Look, I'm "returning" an "out" parameter from my C function here. I can also return an "out" error in form of a "struct * error_return" if I wanted to, with a char * member or whatever.

This is not error handling baked in C either, just like Go. There is nothing "awesome" with doing that. I could do that in any language and nobody would call that "awesome".