I agree with your dispute with the OP's claim, but your claim that "The treatment of structs as full values that could be assigned and passed to or returned fro

I agree with your dispute with the OP's claim, but your claim that "The treatment of structs as full values that could be assigned and passed to or returned from functions was only introduced in ANSI C, 1989" is simply wrong, not at all "on solid ground" -- it came nearly a decade earlier ... but not soon enough to validate the OP's claim that you correctly disputed. I won't comment further.