Hi,
Just for the record: in Drumstick's source tree, directory "utils/vpiano", the
file CMakeLists.txt has the following lines defining the list of libraries that
need to be linked to that program:
TARGET_LINK_LIBRARIES(drumstick-vpiano
${QT_LIBRARIES}
${ALSA_LIBS}
${QT_X11_X11_LIBRARY}
drumstick-common
drumstick-alsa
)
On Tuesday 01 March 2011, Modestas Vainius wrote:
> Hello,
>
> On antradienis 01 Kovas 2011 01:06:22 Pedro Lopez-Cabanillas wrote:
> > I've wrote Drumstick, and I know for sure that the target "vpiano" uses
> > QT_X11_X11_LIBRARY for linking. The bug report says that when linking this
> > target in Debian, it fails saying that -lX11 is required.
> >
> > I suspect that there may be a problem in Debian around this matter. It
> > works fine in some other distros.
>
> Nop, you misunderstood the bug a bit. It does link on Debian or 0.5.0-1 would
> not be in Debian testing. gold linker enables --no-add-needed by default and
> that's typically the reason for packages to fail linking with it. Now ubuntu
> enabled --as-needed by default and gcc maintainer is pushing this to debian
> proper too.
The same policy was introduced in Fedora some time ago, and probably in other
distros as well. Anyway, I understood the problem the first time, and this is
how I've tested the build system here (running openSUSE 11.3)
$ cmake --version
cmake version 2.8.1
$ cmake .. -DCMAKE_EXE_LINKER_FLAGS=-Wl,--no-add-needed
The build process works fine here using this flag. This is the relevant part of
the log:
Linking CXX executable ../../bin/drumstick-vpiano
cd /home/pedro/Projects/drumstick/build/utils/vpiano && /usr/bin/cmake -E
cmake_link_script CMakeFiles/drumstick-vpiano.dir/link.txt --verbose=1
/usr/bin/c++-fexceptions -UQT_NO_EXCEPTIONS -fvisibility=hidden
-fvisibility-inlines-hidden -Wl,--no-add-needed -Wl,--as-needed
CMakeFiles/drumstick-vpiano.dir/moc_pianoscene.cxx.o
CMakeFiles/drumstick-vpiano.dir/moc_pianokeybd.cxx.o
CMakeFiles/drumstick-vpiano.dir/moc_vpianoabout.cxx.o
CMakeFiles/drumstick-vpiano.dir/moc_connections.cxx.o
CMakeFiles/drumstick-vpiano.dir/moc_preferences.cxx.o
CMakeFiles/drumstick-vpiano.dir/moc_vpiano.cxx.o
CMakeFiles/drumstick-vpiano.dir/pianokey.cpp.o
CMakeFiles/drumstick-vpiano.dir/pianoscene.cpp.o
CMakeFiles/drumstick-vpiano.dir/pianokeybd.cpp.o
CMakeFiles/drumstick-vpiano.dir/keylabel.cpp.o
CMakeFiles/drumstick-vpiano.dir/rawkeybdapp.cpp.o
CMakeFiles/drumstick-vpiano.dir/vpianoabout.cpp.o
CMakeFiles/drumstick-vpiano.dir/connections.cpp.o
CMakeFiles/drumstick-vpiano.dir/preferences.cpp.o
CMakeFiles/drumstick-vpiano.dir/vpiano.cpp.o
CMakeFiles/drumstick-vpiano.dir/vpianomain.cpp.o
CMakeFiles/drumstick-vpiano.dir/qrc_pianokeybd.cxx.o -o
../../bin/drumstick-vpiano -rdynamic -L/home/pedro/Projects/drumstick/build/lib
-lQtSvg -lQtGui -lQtDBus -lQtXml -lQtCore -lQtSvg -lQtGui -lQtDBus -lQtXml
-lQtCore -lasound -lX11 ../../lib/libdrumstick-common.a
../../lib/libdrumstick-alsa.so.0.5.1 -lQtSvg -lQtGui -lQtDBus -lQtXml -lQtCore
-lQtSvg -lQtGui -lQtDBus -lQtXml -lQtCore -lasound
-Wl,-rpath,/home/pedro/Projects/drumstick/build/lib
make[3]: Leaving directory `/home/pedro/Projects/drumstick/build'
/usr/bin/cmake -E cmake_progress_report
/home/pedro/Projects/drumstick/build/CMakeFiles 68 69 70 71 72 73 74 75 76 77
78 79 80 81 82 83 84 85 86 87 88 89
[100%] Built target drumstick-vpiano
> So yes, the reason it's failing is that QT_X11_X11_LIBRARY is undefined and --
> no-add-needed no longer looks the library up recursively. The code which sets
> this variable was removed in cmake 2.8.1 by [1]. QT_X11_X11_LIBRARY falls out
> of FindQt4.cmake scope.
You are wrong assuming that the variable QT_X11_X11_LIBRARY is deprecated in
CMake 2.8.1, or it is not available anymore. The CMake macros were reorganized,
and now this variable is set in Qt4ConfigDependentSettings.cmake [2] (lines
259-271) which is included from FindQt4.cmake [3], line 1035, and it is also
documented [4].
The attached CMakeLists.txt test file should work as expected. Here is the
output in my development machine:
$ cmake .
-- The C compiler identification is GNU
-- The CXX compiler identification is GNU
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Looking for Q_WS_X11
-- Looking for Q_WS_X11 - found
-- Looking for Q_WS_WIN
-- Looking for Q_WS_WIN - not found.
-- Looking for Q_WS_QWS
-- Looking for Q_WS_QWS - not found.
-- Looking for Q_WS_MAC
-- Looking for Q_WS_MAC - not found.
-- Found Qt-Version 4.6.3 (using
