[CMake] Relink during install to get correct rpath in the binary?

[Brad King]

Lars Nordlund wrote:
> I was under the impression that CMake automatically did a relink
> against shared libraries during install? I can however not get that to
> happen. I made a shared library and a binary which links against it.
> The rpath is always pointing into my temporary tree of generated
> makefiles and build results. Is there a CMake variable controlling this
> behaviour?

CMake does not relink on installation.  If any of the documentation gave 
you that impression please let me know so it can be fixed.

The rpath feature of CMake is intended to help developers use projects 
with shared libraries from the build tree without setting 
LD_LIBRARY_PATH or their platform's equivalent.  Many linux/unix people 
consider rpaths evil for installed programs, and many linux 
distributions ban them altogether.  The idea is that installed shared 
libraries should be in the system's shared library search path 
(ld.so.conf or equivalent) so they can be shared among applications.

We recommend that when building an appliction for installation that the 
CMake cache variable CMAKE_SKIP_RPATH:BOOL=ON be set to disable 
inclusion of rpaths when linking.  If you want an application to have 
shared libraries in a non-system search path but still find them at 
runtime you can do something like what is done in ParaView 
(www.paraview.org).

ParaView has several executables which share a bunch of code that is 
useful only to those executables.  All the real executables and shared 
libraries get installed in "lib/paraview-2.4/...". Small c-only 
executables that link to nothing get installed in "bin/..." and just set 
the environment properly and exec the real executables.  See here for 
the code:

http://www.paraview.org/cgi-bin/viewcvs.cgi/VTK/Utilities/kwsys/SharedForward.h.in?rev=HEAD&root=ParaView&view=auto
http://www.paraview.org/cgi-bin/viewcvs.cgi/Servers/Executables/pv-forward.c.in?rev=HEAD&root=ParaView&view=auto

This is similar to other applications that use a shell script for the 
same purpose but it doesn't depend on a particular shell syntax and it 
works on Windows too.

-Brad