[PATCH] builds libs by default with full RPATH

[Alexander Neundorf]

On Thursday 20 December 2007, you wrote:
> 2007/12/16, Alexander Neundorf <neundorf at kde.org>:
> > Hi,
> >
> > attached you can find a small patch which changes the default value of
> > the option KDE4_USE_ALWAYS_FULL_RPATH from OFF to ON.
> > A better name for that option would be "KDE_BUILD_LIBS_WITH_RPATH", then
> > I wouldn't have to explain what it does.
> >
> > Pros: libs should always have the correct RPATH
> > Cons: "make install" will take longer, since libs then also have to be
> > relinked (as long as cmake without chrpath support is used)
>
> Hi Alex,
>
> do you know about
> http://people.debian.org/~che/personal/rpath-considered-harmful
> or
> http://wiki.debian.org/RpathIssue
>
> Considering the issues raised there, what's your answer to this?

Set CMAKE_SKIP_RPATH to TRUE, e.g. using "make edit_cache", then you get no 
RPATH at all.

If you have KDE3 and KDE4 installed, you have two different libkdecore. I 
don't see another way than RPATH to get this working (without setting up 
wrapper scripts which set LD_LIBRARY_PATH different for KDE3 and KDE4 apps).

If you want to run an executable from the build tree, with the shared libs in 
the same build tree, you also need RPATH (or wrapper scripts).

Wrapper scripts suck, because the people who want to run the executable have 
to be aware of the fact that they have to run the wrapper script and not the 
actual executable.

Setting up different LD_LIBRARY_PATHs sucks, because you either need wrapper 
scripts as above, or you need to run a script which changes your environment 
from KDE3 to KDE4 and vice versa before running the respective applications.

I didn't differentiate between RPATH and RUNPATH, because in these points the 
differences don't matter.

What sucks about RPATH is that the binutils don't provide a way to change it 
in existing ELF files (Apple added an option for that to the 
link, -max-something-length or so, which does just that, it adds padding to 
the path embedded in the binary for the install name path (which works a bit 
different, but the issue with modifying it is the same)).
And that you can't install libraries to different directories, because then 
the executables won't find them anymore.

Alex

P.S. I sent that email already december 20th, but accidentally without the 
kde-buildsystem address in TO or CC