[CMake] RPATH questions

[Brad King]

Alan W. Irwin wrote:
> On 2006-07-24 11:14-0400 Brad King wrote:
>> Summary:  Just set INSTALL_RPATH on the module target to be the rpath
>> needed in the install tree.  Then things will just work.
> 
> I followed that advice for INSTALL_RPATH with libplplotd, and it worked,
> but
> unlike the build tree case it did not automatically propagate to
> libplplotcxxd.  Here are the ldd results for the install location:
> 
> ldd ~/plplot_cvs/installcmake/lib/libplplotd.so
>         libm.so.6 => /lib/tls/libm.so.6 (0xb7f7b000)
>     libltdl.so.3 => /home/software/autotools/install/lib/libltdl.so.3
> (0xb7f73000)
>     ...
> 
> ldd ~/plplot_cvs/installcmake/lib/libplplotcxxd.so
>         libplplotd.so.9 =>
> /home/software/plplot_cvs/installcmake/lib/libplplotd.so.9 (0xb7fa3000)
>         libltdl.so.3 => /usr/lib/libltdl.so.3 (0xb7f87000)
> 
> Note, the last one is the system libltdl.so location which is out of date
> and which I therefore want to consistently avoid.
> 
> Note, libplplotcxxd has no direct dependencies on libltdl so the only
> reason
> why it even knows about libltdl is through its dependency on the libplplotd
> target.  So why doesn't it automatically pick up the correct INSTALL_RPATH
> information from that target?  Is this a bug in CMake-2.4.2?
> 
> Of course, I can presumably work around this CMake-2.4.2 limitation by
> supplying INSTALL_RPATH information to every target in my project which
> depends on the libplplot target, but there are a lot of targets in my
> project and virtually all of them depend on the libplplot core library so
> this is quite a messy workaround.

No attempt has been made in CMake to implement automatic propagation of
INSTALL_RPATH settings.  This may be added in the future.

For now you'll have to set the rpath on all targets individually.  You
can do this pretty cleanly by creating a macro to make a target a client
of libplplotd:

MACRO(MAKE_PLPLOTD_CLIENT target)
  TARGET_LINK_LIBRARIES(${target} libplpotd)
  SET_TARGET_PROPERTIES(${target} PROPERTIES INSTALL_RPATH ...)
ENDMACRO(MAKE_PLPLOTD_CLIENT)

ADD_LIBRARY(plplotcxxd SHARED ...)
MAKE_PLPLOTD_CLIENT(plplotcxxd)

-Brad