On 10/16/2009 11:06 AM, Mike Edenfield wrote: > On 10/16/2009 12:54 PM, walt wrote: >> On 10/16/2009 04:37 AM, Neil Bothwick wrote: >>> On Fri, 16 Oct 2009 12:20:30 +0100, Peter Humphrey wrote: >>> >>>> I thought I'd have a play with swami, but the emerge fails with >>>> "/bin/sed: can't read /usr/lib64/libogg.la: No such file or directory", >>>> and indeed there is none such. >>> >>> The elog message from the last libogg install explains this. Run >>> lafilefixer --justfixit. >> >> There is no manpage for lafilefixer, but the --help flag prints: >> >> --justfixit Choose some reasonable dirs, such as >> /usr/lib*, etc. , >> find all .la files and fix them to not use >> .la files >> for linking >> >> I can't make sense out of that -- one of the major uses of libtool (I >> thought) >> is for linking. Can anyone 'splain that to me? > > One of the major problems with .la files (besides being mostly useless > on Linux/FreeBSD/any other ELF-based OS) is when they refer to other .la > files instead of linking directly to the binaries. This breaks things > when they get removed from a ebuild for a library that other libraries > depend on. > > The only time that libtool archives provide a real benefit is when > there's a need to link in static libraries that have external > dependencies -- the libtool archive defines the dependency information > that can't be stored in the static archive format. If you don't have > any publicly-consumed static libraries, .la files are just pointless > clutter, so package maintainers very often remove them. Any build > system depending on libtool for its linking then breaks because the > dependency chain is broken. > > Take, for example, this very real example from my system. I have both > hal and dbus installed; hal depends on dbus, and both packages install > libtool archives. In /usr/lib/libhal.la, there is the following: > > # Libraries that this one depends upon. > dependency_libs=' /usr/lib/libdbus-1.la -lcap -lpthread -lrt' > > Thus, whenever a package that uses hal tells libtool to link to > libhal.la, libtool recursively links to libdbus-1.la as well. > > Now, say the dbus maintainer suddenly doesn't like .la files (perhaps a > bad break-up in Los Angeles), and removes them from the ebuild.
I think .la files are an adequate reason to dislike .la files :o) They have certainly wasted many frustrated hours for me. > The > next time I true to use libtool to link in hal, it will fail because the > latest dbus does not include /usr/lib/libdbus-1.la. > > The fix is to run lafilefixer, which changes the above line to say: > > # Libraries that this one depends upon. > dependency_libs=' -L/usr/lib -ldbus-1 -lcap -lpthread -lrt' > > So that hal no longer cares whether or not the dbus package installed > its libtool archive, and all is well. An excellent 'splain, thank you very much :o) Thanks also to Volker for the links to Diego's blogs. I'm about halfway through them now.
