Il giorno mer, 04/08/2010 alle 10.06 +0100, Andrew Haley ha scritto: > > So why if I write: > > big_dummy_t *p = (big_dummy_t*)0; > > uint16_t p = (uint16_t)&(p->singledata); > > > > I get NO warning? > > Because the first is constant folded, the second isn't. Not that it > matters, because your program is undefined anyway, since you're > dereferencing a null pointer. I never read or write data poined by p. I only use it to calculate offset of fields inside it. I could write: uint16_t p = (uint16_t)((char *)&(p->singledata) - (char*)0); thanks
