Am 08.06.2011 15:02, schrieb Eric Noulard:
2011/6/8 Andreas Naumann<andreas-naum...@gmx.net>:
Am 08.06.2011 11:56, schrieb Eric Noulard:
2011/6/8 Andreas Naumann<andreas-naum...@gmx.net>:
Hi @all,
I have some problem with the library usage in cmake.
It seems to me, that cmake removes the full path of the library, if the
path
is in the environment variable LIBRARY_PATH.
This behaviour cause problems at our system, such that the linker links
against the wrong library.
Is there an option to avoid this splitting?
Did you read that:
http://www.cmake.org/Wiki/CMake_RPATH_handling
Which version of CMake are you using?
On which system ?
We are using version 2.8.2 and 2.8.4 on Debian and Suse Linux.
I've read the hints on RPATH handling, but there it is said, that:
"By default if you don't change any RPATH related settings, CMake will link
the executables and shared libraries with full RPATH to all used libraries
in the build tree"
Yes.
And you did not mention it but the probleme you have occurs when using
the executable **directly from the build dir** right?
what do you mean with "using"? I cannot even link the executable,
because cmake removes the path from the library without adding the
directory to the library directories.
This means, if I don't set anything related to RPATH, cmake should not strip
the path from the library, should it?
No it shoudn't for the binary in the buitd tree but...
if you do "make install" the installed binaries will have no RPATH unless
you set
SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
# add the automatically determined parts of the RPATH
# which point to directories outside the build tree to the install RPATH
SET(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
I don't even want to install, just build and use.
I played with the example and it was a bit hard to understand, when the path
is stripped from the library.
The problem arises before linking the executable.
This is a different issue.
Could you copy/paste the
add_executable
and
target_link_libraries
statement you use for the offending executable?
simple:
project("test")
cmake_minimum_required(VERSION 2.8)
set(MYLIB /home/andreas/cmake_test/lib/libfoo.so)
add_executable(foo_exec test.cc)
target_link_libraries(foo_exec ${MYLIB})
So the executable gets the full name and the example works, if the
environment variable library_path is not set to
/home/andreas/cmake_test/lib. The link command is:
/usr/bin/c++ CMakeFiles/foo_exec.dir/test.cc.o -o foo_exec
-rdynamic /home/andreas/cmake_test/lib/libfoo.so
-Wl,-rpath,/home/andreas/cmake_test/lib
If I set LIBRARY_PATH to /home/andreas/cmake_test/lib, the directory is
stripped and the link-command gets:
/usr/bin/c++ CMakeFiles/foo_exec.dir/test.cc.o -o foo_exec
-rdynamic -lfoo
We link to a library, which exists in two different directories:
/usr/lib64
and
somewhere/lib/
This should be resolved by YOU inside CMakeLists.txt by
target_link_libraries(exename /path/to/appropriate/lib/lbname.so)
the
/path/to/appropriate/lib/lbname.so could be the result of an appropriate
find_library
call.
At the same time, the environment variable LIBRARY_PATH is set to
somewhere/lib. In this case, cmake removes the path from the library name,
but does not append it as -L to the linker search paths.
Now it is up to the linker to choose the right library, which is really bad!
In our case (gcc 4.1.2 on Suse) it selects the wrong library.
Is there any possibility to avoid this "environmentvariable dependent"
splitting?
Yes full RPATH should be the solution.
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