[CMake] How not to copy a link

[Michael Hertling]

On 01/06/2012 07:51 PM, Kevin Burge wrote:
> Thanks David.  These are external libraries built outside of CMake, 
> without CMake, not imported via any of the import capabilities of cmake, 
> and that need to be installed alongside my CMake built files.  I think 
> I'm just going to do the install with the rename.  Requires me to be 
> more explicit, but, it's not like it changes all that frequently.

Isn't it sufficient to copy such SONAME symlinks as they are, along with
the actual library files, of course? Having a symlink from the SONAME to
the library file is a basic mean of the ABI management on platforms with
advanced - ;-) - support of shared libraries. Besides, these symlinks
are automatically created by ldconfig when the latter processes the
directory.

Anyway, w.r.t. your initial question, I'd usually suggest to use the
GET_FILENAME_COMPONENT(... REALPATH) command on the symlink prior
to the INSTALL() command, but it seems to not work as expected:

CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
PROJECT(P NONE)
SET(CMAKE_VERBOSE_MAKEFILE ON)
EXECUTE_PROCESS(COMMAND ${CMAKE_COMMAND} -E
    touch xyz.dat.0)
EXECUTE_PROCESS(COMMAND ${CMAKE_COMMAND} -E
    create_symlink xyz.dat.0 xyz.dat)
GET_FILENAME_COMPONENT(XYZ xyz.dat REALPATH)
MESSAGE("XYZ: ${XYZ}")

Due to the documentation of GET_FILENAME_COMPONENT(... REALPATH),

"... the full path with *all* symlinks resolved (REALPATH)."

I'd expect to see

XYZ: .../xyz.dat.0

instead of

XYZ: .../xyz.dat

Do I misunderstand GET_FILENAME_COMPONENT() in respect thereof?

Regards,

Michael

> On 01/06/12 12:45, David Cole wrote:
>> Have you considered setting the VERSION and SOVERSION target
>> properties on your libraries instead of doing the symlinks yourself?
>> CMake will build and install the symlinks automatically for you on
>> platforms where they are supported if you set these target properties.
>>
>> http://www.cmake.org/cmake/help/cmake-2-8-docs.html#prop_tgt:SOVERSION
>> http://www.cmake.org/cmake/help/cmake-2-8-docs.html#prop_tgt:VERSION
>>
>> (Or was that just an example, and you need to do this with other
>> symlink files that are not simply the version symlinks for a
>> library...?)
>>
>>
>> HTH,
>> David