In message <[EMAIL PROTECTED]>, Eric Blake writes: >-----BEGIN PGP SIGNED MESSAGE----- >Hash: SHA1 > >According to Tom G. Christensen on 9/21/2008 2:30 PM: >> cc-3316 cc: ERROR File = handler-unix.c, Line = 490 >> The expression must be a pointer to a complete object type. >> >> ss.ss_sp = extra_stack + extra_stack_size - sizeof (void *); >> ^ > >Yep - gcc allows addition of void*, but many other compilers require an >explicit cast to char * before you can do pointer math (since C89 leaves >pointer math on void* undefined).
C99, too, I believe. The reason being that void is an incomplete type, and has no size. The assumption that you want to add byte-sized chunks is probably not an unreasonable one, and I don't entirely blame gcc for making that guess, but I am obliged to admit that I've more often been wrong than right when I ended up trying to add something to a (void *) pointer. I actually prefer to just require the explicit cast, which makes it unambiguous what type I think I'm counting by. -s
