On Tue, Apr 3, 2012 at 11:17 AM, Mark Hatle <mark.ha...@windriver.com> wrote: > On 4/3/12 1:07 PM, Gary Thomas wrote: >> >> On 2012-04-03 12:03, Mark Hatle wrote: >>> >>> On 4/3/12 12:52 PM, Gary Thomas wrote: >>>> >>>> Why are both opkg-native and rpm-native needed to build images? >>>> When I asked this previously, I was told that rpm was used because >>>> it has superior dependency tracking. Fair enough (I guess), but >>>> then why is opkg required if I build an image using >>>> PACKAGE_CLASSES = "package_rpm" >>>> >>> >>> rpm-native is used for internal dependency scanning. The exact tool is >>> "rpmdeps". These dependencies may or may not be rolled up into package level >>> dependencies by the packaging >>> tool (which may be opkg, deb or rpm). (see package.bbclass) >>> >>> opkg-native is used for handling alternatives and similar during >>> packaging and image creation. So it's also needed. >> >> >> Why? Surely one or the other should be useful for this. I'm sure >> that RedHat doesn't need opkg to build their images... > > > (repeating Paul for the sake of threads when someone searches) > > OE uses the update-alternatives method of handing multiple packages that > provide the same functionality. Packaging systems themselves don't do this, > the helpers do. > > opkg-native provides update-alternatives-cworth (according to Paul E) and > that is needed by the other components in the system to determine which > version of a particular piece of functionality is needed during image > creation. > > There is an "alternative" update-alternatives package, but I don't believe > there is a native version. If anything that is all that should be > required... > > (And RedHat based linux distributions don't have any concept of > alternatives. They generally decide which binary package will provide the > functionality and that is the defacto standard for a given release. OE on > the other hand is closer to Debian based systems in that regard. We can > build multiple packages that may provide the same functionality, then it's > up to the package install time to determine which version of the > functionality is used as the default.)
What's quite interesting to me is that chkconfig has an alternatives command in its source tree which seems to behave just like update-alternatives and is written in C, and includes a man page. See http://www.fastcoder.net/downloads/chkconfig-1.3.30c.tar.gz - ./alternatives.c, ./alternatives.8. I'd suggest we look closer at this rather than continuing to rely on update-alternatives-cworth. -- Christopher Larson _______________________________________________ Openembedded-core mailing list Openembedded-core@lists.openembedded.org http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core
