On Sun, Aug 06, 2017 at 05:24:20PM -0400, Willem de Bruijn wrote: > >> > +#ifdef __KERNEL__ > >> > +#include <linux/time.h> > >> > +#else > >> > +#include <time.h> > >> > +#endif /* __KERNEL__ */ > >> > >> This will break applications that include <linux/time.h> manually. > >> I previously sent a patch to use libc-compat to make compilation succeed > >> when both are included in the case where <linux/time.h> is included after > >> <time.h>. > >> > >> https://lkml.org/lkml/2016/9/12/872 > >> > >> The inverse will require changes to the libc header to avoid redefining > >> symbols already defined by <linux/time.h> > >> > >> The second patch in that 2-patch set included <linux/time.h> > >> unconditionally after the fix. This broke builds that also included > >> <time.h> in the wrong order. I did not resubmit the first patch as a > >> stand-alone, as it is not sufficient to avoid breakage. > > > > I wasn't aware of your change, but I was about to send this to fix the > > case when glibc <time.h> is included before <linux/time.h>: > > > > https://github.com/mcfrisk/linux/commit/f3952a27b8a21c6478d26e6246055383483f6a66 > > There are a few differences between the two. Including <time.h> does not > unconditionally define all the symbols. Some are conditional on additional > state, such as __timespec_defined. Yep, your patch seems better for libc-compat.h. Could you send it again? > > but you also ran into problems where <linux/time.h> is included before > > <time.h> which need fixes in libc header side. > > > > So how to proceed with these? > > The libc-compat change is a good fix that can be submitted on its own. Yes, please do so. > > I don't like leaving a few dozen non-compiling header files into uapi. > > I agree, but I do not see a simple solution. > > Unless libc has the analogous change, including either <time.h> or > <linux/time.h> in userspace can unfortunately cause breakage. > > The added include if __KERNEL__ is defined should be safe, though. Yes, for the kernel side, but your libc-compat change would nice for userspace, where something will break for sure, but providing source API compatibility is sometimes impossible. To summarize, this change from me, and your libc-compat.c for time.h, or? -Mikko -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
