+++ Marcin Juszkiewicz [2012-07-02 12:56 +0200]: > W dniu 02.07.2012 12:52, Wookey pisze: > > +++ P. J. McDermott [2012-07-01 20:00 -0400]: > >> Thibaut and Wookey,
[moving the discussion to debian-embedded - context starts at http://lists.mister-muffin.de/pipermail/debian-bootstrap/2012-July/000248.html if the below doesn't make sense. We are just talking about the fact that cross-gcc packages need a symlink to the actual vX.X cross-gcc (and cpp and g++) binaries in use. This used to be done with alternatives and is now done with a generic gcc-<triplet> package to match the native case. In Debian this latter part isn't being done at all right now so you end up smylinkless] > >> So we need symbolic links, e.g. /usr/bin/arm-linux-gnueabihf-gcc > >> -> arm-linux-gnueabihf-gcc-4.7. Working around this is of course > >> easy, and I've updated my sbuild setup notes [1] accordingly. > > > > At some point Marcin changed things in the ubuntu packaging so now > > there is a package gcc-arm-linux-gnueabi (and cpp-arm-linux-gnueabi) > > which I guess is doing this the same way the gcc native does it. If > > you don't install this package then you don't get a symlink at all > > and the toolchain doesn't work. > > There are gcc-defaults-arm{el,hf}-cross packages in Ubuntu which take > care of symlinks. Going that way was discussed at Emdebian sprint in > February 2011 and everyone agreed. OK. But that was also viewed as an interim arrangement until this multiarch toolchain work was done, so I think we should review this and check we still agree this is the right thing for Debian now. > >> Default Versions of Cross Compilers and Preprocessors > >> ----------------------------------------------------- > > My questions are: how does it work for native gcc? And reason not to > > do the same thing in cross-world? > > Native gcc is selected by 'gcc' package from gcc-defaults. In Ubuntu > cross gcc is selected same way: gcc-triplet is symlink to > gcc-X.Y-triplet (where X.Y of cross == X.Y of native gcc). OK, so do dependencies ensure this package is always installed so you always end up with a symlink?, or do we have to rely on telling people to install the generic cross-compiler package, not a specific cross-compiler package? It does seem to work on ubuntu, I just don't understand how. How do you switch the symlink if you want to use a different version? What is the advantage of this method over /etc/alternatives? Is it just 'doko likes it like this' (which is a relevant argument, I agree) If I understand correctly the advantage of /etc/alternatives is that you always get a symlink, whichever cross-gcc package you install. The advantage of the generic cross-gcc package is that you can install it without know anything about preffered versions (but if you do install a specific version then you don't get a symlink at all). But perhaps it is cleverer than that? BTW: Why are we treating gcc/cpp/g++ differently from binutils and pkg-config and anything else that needs a <triplet>-tool link? I guess gcc packaging allows for installing multiple versions whilst the other don't. Is there a good reason for multiple cross-gcc version support but not other tools? I guess it's just that the package supports this and we have to deal with it. > > Are 'alternatives' sufficient? > > Adding back support for update-alternatives may get blocked by gcc > maintainer (Matthias Klose). OK. That is clearly a consideration. I won't pester him until I actually understand what's happening now and why (or that we don't know why). Wookey -- Principal hats: Linaro, Emdebian, Wookware, Balloonboard, ARM http://wookware.org/ -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
