On Mon, Oct 26, 2020 at 5:44 PM David Laight <David.Laight@xxxxxxxxxx> wrote: > > An alternative would be to add #define ffs(x) our_inline_ffs(x) > before the inline function definition. Yes, that would also work. > I though the idea of the __builtin_ prefix was that you could > have a function with the same name :-( It does multiple things, but one of the things it does is that the ffs() falls back to the libc-provided ffs() function. You can define a global ffs() like the libc implementation does, but defining your own means that it will be used in place of the official one, which is what the warning is for. Arnd