This page is part of the web mail archives of SRFI 13 from before July 7th, 2015. The new archives for SRFI 13 contain all messages, not just those from before July 7th, 2015.
I fear the new string-copy! for one main reason: In all other cases in Scheme, the only difference between a "!" and unmarked procedure with the same name has been the fact that the "!" version modifies (or is at least allowed to modify) its first argument and the unmarked version returns a new object. In this case, the argument specs are different, and I suspect this will be a source of confusion. I suggest fixing this by  renaming the current string-copy! Off-the-cuff suggestion, string-copy-chars! and  adding a non "!" version of the same procedure (e.g., string-copy-chars), to provide the symmetry that there is in the rest of the spec. -dan PS: Olin: Thanks once again for what looks like an excellent draft.