From: Linus Torvalds > Sent: 06 December 2024 18:53 > > On Fri, 6 Dec 2024 at 10:31, Vincent Mailhol <vincent.mailhol@xxxxxxxxx> wrote: > > > > > causes issues when 'x' is not an integer expression (think > > > "is_const(NULL)" or "is_const(1 == 2)". > > > > But 1 == 2 already has an integer type as proven by: > > Yeah, I was confused about exactly what triggers that odd > '-Wint-in-bool-context'. > > It's not about some actual bool type, it's literally a random > collection of integer operations used with logical ops. > > So it's things like "!(var<<2)" that generate that warning, because > some compiler person at some point went "maybe that left shift should > have been just a comparison instead '<'". > > But it turns out that "(var <<2)?0:0" _also_ triggers that warning. > > End result: I have *no* idea how to shut that crazy warning up for > this case, if we want to have some generic macro that says "is this > constant". Because it damn well is perfectly sane to ask "is (a << 3) > a constant expression". I'm missing the compiler version and options to generate the error. Does a '+ 0' help? "(var << 2) + 0 ? 0 : 0" I realised the: #define const_NULL(x) _Generic(0 ? (x) : (char *)0, char *: 1, void *: 0) #define const_true(x) const_NULL((x) ? NULL : (void *)1L)) #define const_expr(x) const_NULL((x) ? NULL : NULL)) I send this morning. Needs 's/char/struct kjkjkjkjui/' applied. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
