https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95177
kargl at gcc dot gnu.org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |kargl at gcc dot gnu.org --- Comment #1 from kargl at gcc dot gnu.org --- Why cast to unsigned char? The prototypes for tolower(), toupper(), isdigit(), etc show that the type of the argument is int. Also, why are errors being issued? None of the places where you have inserted an (unsigned char) cast is a subscripts.