I am trying to build a small Qt (C++) GUI application on Linux but it fails to build with numerous linker errors, complaining about missing dependencies for the Qt library I am linking against. I used ldd on the Qt libraries to verify that the libraries are indeed there - and they are.
My problem seems to be related to the discussion in this thread:
Linking dependencies of a shared library
And while that thread helped me identify my precise problem, it seems that the conclusion of that thread was that my application should link!
The application is compiled with the following command:
g++ -m64 -Wl,-O1 -o Executable some-object.o some-other-object.o -lQtCore -lQtGui -lQtXml -L/usr/lib64 -L/usr/X11R6/lib64 -lpthread
Running this generates warnings of the following form, and linking eventually fails with undefined reference errors (to symbols defined in the 'missing' libraries):
.../ld: warning: libglib-2.0.so.0, needed by /usr/lib64/libQtGui.so, not found (try using -rpath or -rpath-link)
.../ld: warning: libpng14.so.14, needed by /usr/lib64/libQtGui.so, not found (try using -rpath or -rpath-link)
.../ld: warning: libz.so.1, needed by /usr/lib64/libQtGui.so, not found (try using -rpath or -rpath-link)
.../ld: warning: libfreetype.so.6, needed by /usr/lib64/libQtGui.so, not found (try using -rpath or -rpath-link)
and so on (in total there are 18 dependencies that could not be found.)
I can get this to compile if I go and explicitly add -lglib, -lpng14, -lz -lfreetype and so on, but as I mentioned there are 18 dependencies - and I would rather not do that. It also seems that I should not have to do it.
I have compiled the same project on my laptop computer which uses the exact same Linux Distro (openSuse 12.2) without any troubles. All libraries, including Qt, were installed from the distro repositories.
I think this might be some sort of setup problem on my openSuse install, but I have no idea where to start looking to fix this.
Cheers,
Craig
It appears that /usr/lib64/libQtGui.so have hardcoded rpaths in them to locate dependent shared libraries. On one of your hosts the needed libraries are in the expected location while on the other host they are not.
You can use something like elfdump to get the RPATH out of the QT shared library to find out where it will look. Then you can use (I believe) -R on your link command line to point it to where the libraries are actually installed on that host.
EDIT: I think you can do something like objdump -x <binary/library> | grep -i rpath
Related
I am trying to cross-compile apache-qpid for an arm system from a debian.
There is undefined reference to __dlopen error, but it seems that it is related to the previous warning:
using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking ...
Here is the detail:
[ 86%] Linking CXX shared library libqpidcommon.so
CMakeFiles/qpidcommon.dir/qpid/sys/posix/Shlib.cpp.o: In function
`qpid::sys::Shlib::load(char const*)':
/home/mert/qpid-cpp-0.34/src/qpid/sys/posix/Shlib.cpp:32: warning: Using
'dlopen' in statically linked applications requires at runtime the shared
libraries from the glibc version used for linking
/home/mert/IDE/cVEND/00.00.14/bin/../arm-feig-linux-
gnueabi/sysroot/usr/lib/libdl.a(dlopen.o): In function `dlopen':
dlopen.c:(.text+0xc): undefined reference to `__dlopen'
I do not know what is happening exactly and how to solve it.
Here there is a similiar thing, I tried to add -static -ldl -lc C_FLAGS but made no difference.
Any help appreciated.
EDIT :
EDIT :
I am not sure exactly what is solved the problem, but I think that -ldl was looking exactly for libdl.so, but in arm directory, it was libdl-2.19.so, thus, probably it was then looking for and finding in another directory. I have linked libdl.so to libdl-2.19.so and now it is compiling.
The linker needs the options, not the compiler. See LDFLAGS.
https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html
Extra flags to give to compilers when they are supposed to invoke the
linker, ‘ld’, such as -L. Libraries (-lfoo) should be added to the
LDLIBS variable instead.
If this error occurs during the make step try doing
make LIBS=-ldl
And make sure the library path is present in LDFLAGS
export LDFLAGS=-L<path/to/ldl>
I'm trying to compile a program on Ubuntu 11.10 that uses the Boost libraries. I have the 1.46-dev Boost libraries from the Ubuntu Repository installed, but I get an error when compiling the program.
undefined reference to boost::system::system_category()
What is it that I do wrong?
The boost library you are using depends on the boost_system library. (Not all of them do.)
Assuming you use gcc, try adding -lboost_system to your compiler command line in order to link against that library.
Linking with a library that defines the missing symbol (-lboost_system) is the obvious solution, but in the particular case of Boost.System, a misfeature in the original design makes it use boost::system::generic_category() and boost::system::system_category() needlessly. Compiling with the flag -DBOOST_SYSTEM_NO_DEPRECATED disables that code and lets a number of programs compile without requiring -lboost_system (that link is of course still needed if you explicitly use some of the library's features).
Starting from Boost 1.66 and this commit, this behavior is now the default, so hopefully fewer and fewer users should need this answer.
As noticed by #AndrewMarshall, an alternative is to define BOOST_ERROR_CODE_HEADER_ONLY which enables a header-only version of the code. This was discouraged by Boost as it can break some functionality. However, since 1.69, header-only seems to have become the default, supposedly making this question obsolete.
Another workaround for those who don't need the entire shebang: use the switch
-DBOOST_ERROR_CODE_HEADER_ONLY.
If you use CMake, it's add_definitions(-DBOOST_ERROR_CODE_HEADER_ONLY).
The above error is a linker error... the linker a program that takes one or more objects generated by a compiler and combines them into a single executable program.
You must add -lboost_system to you linker flags which indicates to the linker that it must look for symbols like boost::system::system_category() in the library libboost_system.so.
If you have main.cpp, either:
g++ main.cpp -o main -lboost_system
OR
g++ -c -o main.o main.cpp
g++ main.o -lboost_system
When using CMAKE and find_package, make sure it is :
find_package(Boost COMPONENTS system ...)
and not
find_package(boost COMPONENTS system ...)
Some people may have lost hours for that ...
I got the same Problem:
g++ -mconsole -Wl,--export-all-symbols -LC:/Programme/CPP-Entwicklung/MinGW-4.5.2/lib -LD:/bfs_ENTW_deb/lib -static-libgcc -static-libstdc++ -LC:/Programme/CPP-Entwicklung/boost_1_47_0/stage/lib \
D:/bfs_ENTW_deb/obj/test/main_filesystem.obj \
-o D:/bfs_ENTW_deb/bin/filesystem.exe -lboost_system-mgw45-mt-1_47 -lboost_filesystem-mgw45-mt-1_47
D:/bfs_ENTW_deb/obj/test/main_filesystem.obj:main_filesystem.cpp:(.text+0x54):
undefined reference to `boost::system::generic_category()
Solution was to use the debug-version of the system-lib:
g++ -mconsole -Wl,--export-all-symbols -LC:/Programme/CPP-Entwicklung/MinGW-4.5.2/lib -LD:/bfs_ENTW_deb/lib -static-libgcc -static-libstdc++ -LC:/Programme/CPP-Entwicklung/boost_1_47_0/stage/lib \
D:/bfs_ENTW_deb/obj/test/main_filesystem.obj \
-o D:/bfs_ENTW_deb/bin/filesystem.exe -lboost_system-mgw45-mt-d-1_47 -lboost_filesystem-mgw45-mt-1_47
But why?
When I had this, problem, the cause was the ordering of the libraries. To fix it, I put libboost_system last:
g++ mingw/timer1.o -o mingw/timer1.exe -L/usr/local/boost_1_61_0/stage/lib \
-lboost_timer-mgw53-mt-1_61 \
-lboost_chrono-mgw53-mt-1_61 \
-lboost_system-mgw53-mt-1_61
This was on mingw with gcc 5.3 and boost 1.61.0 with a simple timer example.
in my case, adding -lboost_system was not enough, it still could not find it in my custom build environment. I had to use the advice at Get rid of "gcc - /usr/bin/ld: warning lib not found" and change my ./configure command to:
./configure CXXFLAGS="-I$HOME/include" LDFLAGS="-L$HOME/lib -Wl,-rpath-link,$HOME/lib" --with-boost-libdir=$HOME/lib --prefix=$HOME
for more details see Boost 1.51 : "error: could not link against boost_thread !"
...and in case you wanted to link your main statically, in your Jamfile add the following to requirements:
<link>static
<library>/boost/system//boost_system
and perhaps also:
<linkflags>-static-libgcc
<linkflags>-static-libstdc++
I have a problem, i want to compile my application with static linking of mysql connector.
My command line:
g++ -o newserver stdafx.cpp ... -lboost_system -lboost_thread
-lpthread -lmysqlcppconn -static /usr/lib/libmysqlcppconn-static.a -std=c++0x
But i have error:
/usr/bin/ld: cannot find -lmysqlcppconn
/tmp/ccxpOfdZ.o: In function `IsEqualsDns(unsigned long, std::basic_string<char, std::char_traits<char>, std::allocator<char> >)':
Server.cpp:(.text+0x356e): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
collect2: ld returned 1 exit status
How can i fix this?
Thanks!
Where is the library libsqlcppconn.a or libsqucppconn.so
(static or dynamic)? The compiler is looking for it, and
doesn't find it.
Presumably, this is the same library as
/usr/lib/mysqlcppconn-static.a. If so, just drop the
-lmysqlcppconn. Or just use -lmysqlcppconn-static (no
spaces), and forget about the /usr/lib/libmysqlconn-static.a.
With a name like that, there shouldn't be a corresponding .so,
which means that g++ will link it statically, even without the
-static. You only need the -static if there is both
a libmysqlconn-static.so and a libmysqlconn-static.a in the
same directory.
With regards to the second error (which is just a warning, but
will cause problems if you try to run the linked program on
other machines, or even after an upgrade of your machine): if
you use -static anywhere in your command line (as you
currently do), then it applies to all files linked afterwards.
Including the system libraries, which you don't want to link
statically. My guess is that the -static isn't necessary (see
above); if it is, place it immediately before the library you
want to link statically, and place a -dynamic immediately
after (so that any following libraries, including the system
libraries, will be dynamically linked).
You could try g++ -static YOUR ARGUMENTS.
If you are coming from a Windows platform, linking against Boost can give a few surprises. The typicall Boost installation (e.g. after ./b2 install) will make both dynamic and static libraries and put them in the same directory. Typically, the two library forms only differ in their extension (.so or .a).
Windows supports auto-linking, which basically means that library files contain some flags in their first few bytes indicating whether they are for dynamic or for static linking. On Linux platforms, this is not the case and the linker gets confused which file to load (since you don't provide the extension of the library name). Therefore, you need to tell your linker which form of linking you want.
I was trying to reinstall my ffmpeg, following this guide, on my ARM Ubuntu machine. Unfortunately, when I compile a program which uses this lib I get the following failure:
/usr/bin/ld: /usr/local/lib/libavcodec.a(amrnbdec.o): relocation R_ARM_MOVW_ABS_NC against `a local symbol' can not be used when making a shared object; recompile with -fPIC
/usr/local/lib/libavcodec.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
Now I would like to recompile it with -fPIC like the compiler is suggesting but I have no idea how. Any help is appreciated.
Briefly, the error means that you can't use a static library to be linked w/ a dynamic one.
The correct way is to have a libavcodec compiled into a .so instead of .a, so the other .so library you are trying to build will link well.
The shortest way to do so is to add --enable-shared at ./configure options. Or even you may try to disable shared (or static) libraries at all... you choose what is suitable for you!
Have a look at this page.
you can try globally adding the flag using: export CXXFLAGS="$CXXFLAGS -fPIC"
I had this problem when building FFMPEG static libraries (e.g. libavcodec.a) for Android x86_64 target platform (using Android NDK clang). When statically linking with my library the problem occured although all FFMPEG C -> object files (*.o) were compiled with -fPIC compile option:
x86_64/libavcodec.a(h264_qpel_10bit.o):
requires dynamic R_X86_64_PC32 reloc against 'ff_pw_1023'
which may overflow at runtime; recompile with -fPIC
The problem occured only for libavcodec.a and libswscale.a.
Source of this problem is that FFMPEG has assembler optimizations for x86* platforms e.g. the reported problem cause is in libavcodec/h264_qpel_10bit.asm -> h264_qpel_10bit.o.
When producing X86-64 bit static library (e.g. libavcodec.a) it looks like assembler files (e.g. libavcodec/h264_qpel_10bit.asm) uses some x86 (32bit) assembler commands which are incompatible when statically linking with x86-64 bit target library since they don't support required relocation type.
Possible solutions:
compile all ffmpeg files with no assembler optimizations (for ffmpeg this is configure option: --disable-asm)
produce dynamic libraries (e.g. libavcodec.so) and link them in your final library dynamically
I chose 1) and it solved the problem.
Reference: https://tecnocode.co.uk/2014/10/01/dynamic-relocs-runtime-overflows-and-fpic/
After the configure step you probably have a makefile. Inside this makefile look for CFLAGS (or similar). puf -fPIC at the end and run make again. In other words -fPIC is a compiler option that has to be passed to the compiler somewhere.
If you're building a shared library but need to link with static libavcodec add linker flags:
-Wl,-Bsymbolic
In case of cmake:
set(CMAKE_SHARED_LINKER_FLAGS "-Wl,-Bsymbolic")
I hit this same issue trying to install Dashcast on Centos 7. The fix was adding -fPIC at the end of each of the CFLAGS in the x264 Makefile. Then I had to run make distclean for both x264 and ffmpeg and rebuild.
In addirion to the good answers here, specifically Robert Lujo's.
I want to say in my case I've been deliberately trying to statically compile a version of ffmpeg. All the required dependencies and what else heretofore required, I've done static compilation.
When I ran ./configure for the ffmpeg process I didnt notice --enable-shared was on the commandline. Removing it and running ./configure is only then I was able to compile correctly (All 56 mbs of an ffmpeg binary). Check that out as well if your intention is static compilation
I'm building ffmpeg 5.1.2 on CentOS7 with gcc4.8.5.
As mentioned in ${ffmpegRoot}/doc/platform.texi:
1)configure with option
"--enable-pic"
2)add the following option to your project LDFLAGS
"-Wl,-Bsymbolic"
Before compiling make sure that "rules.mk" file is included properly in Makefile or include it explicitly by:
"source rules.mk"
I am trying to compile my gcc code using the following make command .
OS :Redhat ,gcc - 4.1
But I am getting error as follows :
rmtrain#lintrni130 $ /usr/local/bin/make all
[ 21%] Built target GCVCore
Linking CXX executable CFE
/usr/bin/ld: warning: libicui18n.so.36, needed by ../../Generic/icu/lib/libicuio.so, not found (try using -rpath or -rpath-link)
/usr/bin/ld: warning: libxalanMsg.so.110, needed by ../../Generic/Xalan/lib/libxalan-c.so, not found (try using -rpath or -rpath-link)
CMakeFiles/CFE.dir/trnuser1/rmtrain/DevelopmentEnv/Generic/ConvUI/GCVConvUISetting.o: In function `xercesc_2_6::XMLAttDefList::~XMLAttDefList()':
GCVConvUISetting.cpp:(.text._ZN11xercesc_2_613XMLAttDefListD0Ev[xercesc_2_6::XMLAttDefList::~XMLAttDefList()]+0x2f): undefined reference to `xercesc_2_6::XMemory::operator delete(void*)'
Please Help with this .
The warnings means that some libraries you link to have dependencies on other shared libraries, and those libraries weren't found in the linker's search path. The linker manual describes how it forms that search path in the docs for the -rpath-link option
They're only warnings, so haven't caused your link to fail. It will be a problem if those required libs aren't found at run-time, but is not necessarily a problem at link-time.
If you want to silence the warnings you will need to find out which directory contains libicui18n.so.36 and libxalanMsg.so.110 and use one of the methods described in the manual to tell the linker to look in that directory.
The last line is the real problem, and indicates you are not linking to the library which defines that symbol. You'll need to find out which library it is and link to it with -lfoo, it will probably be something like -lxerces
i reinstalled icu 3.2 instead of 3.6.It worked fine then.