Re: [CMake] transitive linking with separate projects
Hello Michael, Am 2012-03-06 16:46, schrieb Michael Hertling: or possibly better: # libbar/bar-config.cmake.in: FIND_PACKAGE(FOO PATHS @FOO_DIR@ NO_DEFAULT_PATH) I used FIND_PACKAGE(FOO 0.1.0 REQUIRED) in the package config file now, which works, too. BTW, find modules / config files should provide a *_LIBRARIES variable even if they use imported targets, e.g.: SET(FOO_LIBRARIES foo-shared) I added this. Let me guess, this is for convenience with find rules using the same variables? PS: The baz project on GitHub only contains a README. I forgot to push this one. Thanks very much, I guess this solves this kind of problem with my packages. :-) Greets Alex -- »With the first link, the chain is forged. The first speech censured, the first thought forbidden, the first freedom denied, chains us all irrevocably.« (Jean-Luc Picard, quoting Judge Aaron Satie) *** GnuPG-FP: 02C8 A590 7FE5 CA5F 3601 D1D5 8FBA 7744 CC87 10D0 *** -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] transitive linking with separate projects
On 03/07/2012 11:29 AM, Alexander Dahl wrote: Hello Michael, Am 2012-03-06 16:46, schrieb Michael Hertling: or possibly better: # libbar/bar-config.cmake.in: FIND_PACKAGE(FOO PATHS @FOO_DIR@ NO_DEFAULT_PATH) I used FIND_PACKAGE(FOO 0.1.0 REQUIRED) in the package config file now, which works, too. Actually, FIND_PACKAGE(FOO PATHS @FOO_DIR@ NO_DEFAULT_PATH) is meant to ensure that bar-config.cmake loads the *same* foo-config.cmake as bar's CMakeLists.txt has before. Possibly, it's even the best to use exactly the same parameters - apart from PATHS and NO_DEFAULT_PATH - i.e., version, components, external variables etc., in order to guarantee that really the same foo-targets.cmake is included. BTW, find modules / config files should provide a *_LIBRARIES variable even if they use imported targets, e.g.: SET(FOO_LIBRARIES foo-shared) I added this. Let me guess, this is for convenience with find rules using the same variables? Yes, in this way, it works with imported targets as well as full paths. PS: The baz project on GitHub only contains a README. I forgot to push this one. Thanks very much, I guess this solves this kind of problem with my packages. :-) See also [1]. Regards, Michael [1] http://public.kitware.com/Bug/view.php?id=12588 -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
[CMake] transitive linking with separate projects
Hei hei, we faced a build problem with transitive linking of separate projects where I can't find the right solution on my own. I hope someone can give me a hint. I prepared a test case with two libraries libfoo and libbar and an application baz. libfoo is on his own, libbar calls a function from libfoo and baz calls the function from libbar calling libfoo. So the dependencies are like this: baz - libbar - libfoo baz doesn't need to know of libfoo because it just calls libbar, so I thought. Now the projects are separated and both libraries come with cmake package configuration files. For linking libfoo in libbar I do the following: find_package(FOO) target_link_libraries(BAR_SRC foo-shared) foo-shared is the target libfoo exports via cmake package configuration. This works and ldd shows libbar is correctly linked against libfoo. Now when compiling baz I more or less do the same: find_package(BAR) target_link_libraries(BAZ_SRC bar-shared) However building baz fails with the following error: % make [100%] Building C object src/CMakeFiles/baz.dir/baz.c.o Linking C executable baz /usr/bin/ld: cannot find -lfoo-shared collect2: ld returned 1 exit status make[2]: *** [src/baz] Fehler 1 make[1]: *** [src/CMakeFiles/baz.dir/all] Fehler 2 make: *** [all] Fehler 2 It seems like cmake tries to link against libfoo here but does not know anything about it. If I add find_package(FOO) to baz obviously the target is imported from libfoo cmake package files. The question is, if I know nothing about the requirements of libbar and want to avoid adding find_package statements for those requirements to baz, how would I do this? I put all the code on GitHub, so if someone maybe could have a look? https://github.com/LeSpocky/libfoo https://github.com/LeSpocky/libbar https://github.com/LeSpocky/baz Greets Alex -- »With the first link, the chain is forged. The first speech censured, the first thought forbidden, the first freedom denied, chains us all irrevocably.« (Jean-Luc Picard, quoting Judge Aaron Satie) *** GnuPG-FP: 02C8 A590 7FE5 CA5F 3601 D1D5 8FBA 7744 CC87 10D0 *** -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] transitive linking with separate projects
On 03/06/2012 02:47 PM, Alexander Dahl wrote:
Hei hei,
we faced a build problem with transitive linking of separate projects
where I can't find the right solution on my own. I hope someone can give
me a hint. I prepared a test case with two libraries libfoo and libbar
and an application baz. libfoo is on his own, libbar calls a function
from libfoo and baz calls the function from libbar calling libfoo. So
the dependencies are like this:
baz - libbar - libfoo
baz doesn't need to know of libfoo because it just calls libbar, so I
thought.
Now the projects are separated and both libraries come with cmake
package configuration files. For linking libfoo in libbar I do the
following:
find_package(FOO)
target_link_libraries(BAR_SRC foo-shared)
foo-shared is the target libfoo exports via cmake package
configuration. This works and ldd shows libbar is correctly linked
against libfoo.
Now when compiling baz I more or less do the same:
find_package(BAR)
target_link_libraries(BAZ_SRC bar-shared)
However building baz fails with the following error:
% make
[100%] Building C object src/CMakeFiles/baz.dir/baz.c.o
Linking C executable baz
/usr/bin/ld: cannot find -lfoo-shared
collect2: ld returned 1 exit status
make[2]: *** [src/baz] Fehler 1
make[1]: *** [src/CMakeFiles/baz.dir/all] Fehler 2
make: *** [all] Fehler 2
It seems like cmake tries to link against libfoo here but does not know
anything about it. If I add find_package(FOO) to baz obviously the
target is imported from libfoo cmake package files. The question is, if
I know nothing about the requirements of libbar and want to avoid adding
find_package statements for those requirements to baz, how would I do
this?
I put all the code on GitHub, so if someone maybe could have a look?
https://github.com/LeSpocky/libfoo
https://github.com/LeSpocky/libbar
https://github.com/LeSpocky/baz
Greets
Alex
If you run grep foo -r libbar-install-dir/lib/cmake/bar, you will
see only one line which informs the user of bar-config.cmake that the
bar-shared target has a prerequisite name foo-shared, but there is no
more information. For this reason, it's passed as -lfoo-shared to the
linker. You need to include foo-targets.cmake in bar-config.cmake in
order to make the necessary information available, e.g. by
# libbar/bar-config.cmake.in:
INCLUDE(@FOO_CONFIG@)
get_filename_component(_dir ${CMAKE_CURRENT_LIST_FILE} PATH)
get_filename_component(_prefix ${_dir}/../../.. ABSOLUTE)
include(${_dir}/@PROJECT_NAME@-targets.cmake)
set(BAR_INCLUDE_DIRS ${_prefix}/include/@PROJECT_NAME@)
or possibly better:
# libbar/bar-config.cmake.in:
FIND_PACKAGE(FOO PATHS @FOO_DIR@ NO_DEFAULT_PATH)
get_filename_component(_dir ${CMAKE_CURRENT_LIST_FILE} PATH)
get_filename_component(_prefix ${_dir}/../../.. ABSOLUTE)
include(${_dir}/@PROJECT_NAME@-targets.cmake)
set(BAR_INCLUDE_DIRS ${_prefix}/include/@PROJECT_NAME@)
This will make the user of bar-config.cmake include the same foo-
config.cmake and, thus, foo-targets.cmake that bar's CMakeLists.txt
has included, too. See also FIND_PACKAGE()'s NAMES / CONFIGS clauses.
BTW, find modules / config files should provide a *_LIBRARIES variable
even if they use imported targets, e.g.: SET(FOO_LIBRARIES foo-shared)
Regards,
Michael
PS: The baz project on GitHub only contains a README.
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