Notice: taglib-extras required

[Andreas Pakulat]

On 21.03.09 13:09:46, Andreas Pakulat wrote:
> On 21.03.09 12:55:15, Mark Kretschmann wrote:
> > On Thu, Mar 19, 2009 at 3:19 PM, Jeff Mitchell <mitchell at kde.org> wrote:
> > > Taglib-Extras is now a required dependency of Amarok from SVN.  You can
> > > find it in the trunk/kdesupport/taglib-extras directory of KDE's SVN
> > > tree.  You will need to either build it yourself, or wait for packagers
> > > to come out with a package for it.
> > 
> > Just a note for those of you installing Amarok and taglib-extras in
> > your $HOME: If you get linker errors while building Amarok, put this
> > (it works for me) in your .bashrc, or type it manually before
> > compiling ;)
> > 
> > "export LD_LIBRARY_PATH=$HOME/kde/build/taglib-extras/taglib-extras"
> > 
> > 
> > PS:
> > I'm still hoping that it might be possible to fix our CMake scripts to
> > make this step unnecessary, but I don't know how. Any CMake experts
> > here? Please speak up now! ;)
> 
> Are the errors about libraries that taglib-extras links against or from
> amarok code missing taglib-extras? Usually KDE apps automatically set
> rpath on their binary (because FindKDE4Internal.cmake sets a cmake flag
> to always use rpath), so the export above shouldn't be necessary as long
> as CMake knows the proper absolute path to the taglib-extras library
> when building amarok.
> 
> I'm currently rebuilding all of kde4 so should see this soon myself as
> well. At least I can't see any obvious errors from a quick look through
> amarok's CMakeLists.txt or the FindTagLib-Extras.cmake module.

Ah, now I see the problem. The taglib-extras-config script produces
pkg-config like output with -L/path and -lsomelib. However when you pass
this combo to cmake it doesn't know that the given -L path corresponds
to the given lib, so it doesn't put that path into the RPATH of the
executable/library it builds.

Seeing that taglib-extras also ships with a .pc file, why not use the
existing pkg-config macros which already do the "dirty" work? It does
require to set another env var for pkg-config to find the .pc files, but
you have to set some variable anyway if you're installing to $HOME (i.e.
PATH).

Attached is a patch for FindTagLib-Extras.cmake using pkg_check_modules
similar to how this is used in kdelibs for various Find-modules that use
pkg-config. It still supports win32 debug-postfix and also supports
finding the lib when no pkg-config file is found. It prefers pkg-config
supplied lib/includedir over kde4 or amarok installation dir or standard
paths like /usr(/local) or stuff mentioned in CMAKE_PREFIX_PATHS. The
only downside is that I had to copy a little bit of cmake-code from
kdelibs (for the win32 debug) and that the pkg_check_modules call will
print out it found taglib-extras even if the Find-Module will do some
more checks. The reason for these is that apparently parts of amarok can
be built without kdelibs but with taglib-extras.

I've built amarok and taglib-extras into two different dirs in my $HOME
(kde4 is built into /usr/local) and with just setting PKG_CONFIG_PATH at
least utilities/collection* does build and link properly. 

So let me know if this patch is ok, then I'll commit it.

Andreas

PS: I also renamed TAGLIB-EXTRAS_INCLUDES to TAGLIB-EXTRAS_INCLUDE_DIR
which seems to be the preferred name (judging by kdelibs find-modules)
 
-- 
Write yourself a threatening letter and pen a defiant reply.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: amarok_improve_findtaglib-extras.diff
Type: text/x-diff
Size: 9172 bytes
Desc: not available
URL: <http://mail.kde.org/pipermail/amarok/attachments/20090321/84e907af/attachment.bin>