Suppose KX or you delivered a spec, what would you see in a column vector file?
length of the list
index (list or lists of list, offsets)
The flags take constant time to read or write thru Q programs.
The length takes constant time to update if you append to a noattr list. You may need to update the sorted flag. Why don't you just upsert in Q?
The index will probably take linear time to update in the general case, i.e. rewriting the whole thing. Why don't you just rewrite in Q?
The satellite data will probably take linear time to update, too. Why don't you just rewrite in Q?
I have read your last few posts. Random access in-place overwrite to a particular element is the only usage that you can do in C but not Q. Are there anything else that you want to bypass Q and do in C?