https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110333
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The 4095 comes from the C standard I think. Even latest C23 draft says in 7.23.6.1 "The number of characters that can be produced by any single conversion shall be at least 4095." so it is I think a portability warning.