On Mon, 20 Nov 2017, Aurelien Jarno wrote:
> On 2017-11-20 21:58, Mikulas Patocka wrote: > > > > > > On Mon, 20 Nov 2017, Samuel Thibault wrote: > > > > > Mikulas Patocka, on lun. 20 nov. 2017 19:13:31 +0100, wrote: > > > > There is package libc6-amd64:i386 and libc6-amd64:x32 (which provide > > > > x86-64 libc in /lib64/). This package is not technically needed (because > > > > x86-64 libc is already installed in /lib/x86_64-linux-gnu/), but it is > > > > installed nonetheless because of some dependencies. > > > > > > The issue of libc6-amd64:i386 conflicting with libc6:amd64 is not new, I > > > tried to do it in the past, just to see, with the same kind of effect as > > > you had. > > > > > > The question is rather how that got pulled at all. What package thinks > > > it's a good idea to pull libc6-amd64? Apart from libc64* packages > > > (which should normally not get pulled either), I can see uc-echo which > > > should rather use foreign dependencies, and :i386 multilib packages > > > which don't really make sense to install either. > > > > > > I don't remember whether it was tried to make libc6-amd64:i386 conflict > > > with libc6:amd64 (and vice-versa for i386) to make sure that this > > > doesn't happen by misfortune? > > > > > > Samuel > > > > libc6-amd64 is pulled by lib64asan0, lib64asan1, lib64asan2, lib64asan3, > > lib64asan4, lib64atomic1, lib64cilkrts5, lib64gcc1, lib64gomp1, lib64itm1, > > lib64quadmath0, lib64stdc++6, lib64ubsan0, libc6-dev-amd64. > > > > If you install gcc-7-multilib for non-default architecture (i386 or x32), > > it will inevitably pull libc6-amd64. > > What's the point of doing that, as opposed for example building with > -m32 or mx32? The native x32 gcc binary is about 10% faster than the amd64 binary. > > If we removed libc6-amd64 at all, it would cause problems building amd64 > > packages on i386 system. We could make those lib64* packages dependent on > > libc6:amd64 instead, but that would break if the user has i386 > > installation and he doesn't have amd64 foreign architecture set up. > > > > It would be best to set it up so that libc6-amd64 doesn't install any > > files only if libc6:amd64 is present. Could it be done with the deb > > format? > > It's not something possible, and it's even more complicated than that. > The current ugly way the multiarch + multilib is done, uses a different > libc for linking and executing. So you definitely need to install both > if you want to be able to build and execute code. > > -- > Aurelien Jarno GPG: 4096R/1DDD8C9B > aurel...@aurel32.net http://www.aurel32.net Mikulas
