On Tue, 02 Jan 2024 15:56:00 -0800 Kaz Kylheku <k...@kylheku.com> wrote:
> On 2024-01-02 15:25, Takashi Yano via Cygwin wrote: > > On Tue, 02 Jan 2024 14:18:15 -0800 > > Kaz Kylheku via Cygwin <cygwin@cygwin.com> wrote: > >> I noticed that this macro, defined in winsup/cygwin/local_includes/path.h: > >> > >> #define isdrive(s) (isalpha (*(s)) && (s)[1] == ':') > >> > >> is being used with arguments of type char, like dereferenced "char *" > >> pointers. > >> > >> Unless the isalpha implementation is robust against this, it should be > >> isalpha((unsigned char) *(s)). > > > > > > https://cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=newlib/libc/ctype/ctype_.h;h=a73870b3e4ade5545fd41bcc6f10446a22b4b46e;hb=HEAD > > I see, so on Cygwin, the negative index is allowed, thanks to a displacement. > > # define DEFAULT_CTYPE_PTR ((char *) _ctype_b + 127) > > But, 127? A (signed) char can go to -128. '\x80' will access _ctype_b[-1]. Is > that also somehow OK? > > (Tangential remark: all ctype implementations have to handle at least one > negative value, namely EOF.) https://cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=newlib/libc/ctype/isalpha.c;h=8b8e78a296359a4a8b3687fd76b1b73cd707a6da;hb=HEAD Perhaps, the off-by-one is for EOF as you guess. -- Takashi Yano <takashi.y...@nifty.ne.jp> -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
