There's one other thing that's different in those early Cs, there was no union, and structs worked differently. Effectively a field in a struct was just an offs

There's one other thing that's different in those early Cs, there was no union, and structs worked differently. Effectively a field in a struct was just an offset, and all offset names were part of a global namespace of all field offsets - you could use any field name with any struct pointer - which is how you did the equivalent of unions - the v6/v7 unix kernels used that for block device structures, they all began with the same first fields (a block queue) followed by per-device stuff