Re: drivers/infiniband/hw/qib/qib_sysfs.c:413:1: error: static_assert expression is not an integral constant expression

From: Jason Gunthorpe
Date: Mon Sep 13 2021 - 15:04:55 EST


On Mon, Sep 13, 2021 at 11:53:25AM -0700, Nathan Chancellor wrote:
> On Mon, Sep 13, 2021 at 03:38:13PM -0300, Jason Gunthorpe wrote:
> > On Mon, Sep 13, 2021 at 10:00:02AM -0700, Nick Desaulniers wrote:
> >
> > > > This macro would like to know that the passed in member name has a u64
> > > > type, all the things I've come up with fail on clang - but many work
> > > > fine on gcc. Frankly I think this case is a clang bug myself..
> > >
> > > Perhaps, though this assertion looks a bit like offsetof() to me. I
> > > wonder if that can help here?
> >
> > The assertion would logically like to be this:
> >
> > static_assert(typecheck(((struct qib_port *)0)->N, u64))
>
> This works for me with both GCC and clang, if that is acceptable to you?
> It fails if you change one of the variables to 'u32'.

Yes, thanks. Can't say I've even heard of __same_type before :\ would
be nice if this was in typecheck.h along with the other variations of
the same idea. Presumably it is a little bit different from those
somehow?

Jason