On Mon, Mar 01, 2021 at 06:01:36PM +0000, Andrew Cooper wrote: > On 01/03/2021 17:59, Andrew Cooper wrote: > > On 01/03/2021 09:58, Roger Pau Monne wrote: > >> clang++ relies on the C++ headers installed by g++, or else a clang > >> build will hit the following error: > >> > >> <built-in>:3:10: fatal error: 'cstring' file not found > >> #include "cstring" > >> ^~~~~~~~~ > >> 1 error generated. > >> make[10]: *** [Makefile:120: headers++.chk] Error 1 > >> > >> Reported-by: Stefano Stabellini <[email protected]> > >> Signed-off-by: Roger Pau Monné <[email protected]> > >> --- > >> Cc: Ian Jackson <[email protected]> > >> No real risk here from a release PoV, it's just pulling a package > >> required for the Alpine clang build. Worse that cold happen is that > >> the Alpine clang build broke, but it's already broken. > > Shouldn't this be fixed upstream in Alpine? Its clearly a packaging bug. > > Or (thinking about it), we've got a build system bug using g++ when it > should be using clang++.
No, the check is using clang++, the issue is that clang++ doesn't install the standard c++ headers, and thus trying to use them (cstring in this case) fails. Installing the g++ package solves the issue because it installs the headers. > How does this check work (without g++) on a non-clang build? It works because on a non-clang Alpine build g++ wasn't installed, so the check wasd just skipped. The headers++.chk target in xen/include/Makefile has a explicit check for a functional CXX. I do think this is some kind of error in the Alpine clang package, as I assume installing clang++ without the standard c++ headers is an error. Regardless of that, I also think installing g++ on the Alpine container is fine, as we would then also perform the C++ header checks with g++ on the normal build. Thanks, Roger.
