I'm trying to test out a new dev environment and I am having some problems referencing some of the required Qt libraries.
First I ran this:
$ g++ HelloWorld.C -o HelloWorld -I /usr/local/Trolltech/Qt-4.5.1/include/QtCore/ -I /usr/local/Trolltech/Qt-4.5.1/include/
and got this error:
/tmp/ccmsm4kZ.o: In function `QString::QString(char const*)':
HelloWorld.C:(.text._ZN7QStringC2EPKc[_ZN7QStringC5EPKc]+0x1d): undefined reference to `QString::fromAscii_helper(char const*, int)'
/tmp/ccmsm4kZ.o: In function `QString::~QString()':
HelloWorld.C:(.text._ZN7QStringD2Ev[_ZN7QStringD5Ev]+0x2d): undefined reference to `QString::free(QString::Data*)'
collect2: ld returned 1 exit status
So then I added reference to the QtCore library via:
$ g++ HelloWorld.C -o HelloWorld -I /usr/local/Trolltech/Qt-4.5.1/include/QtCore/ -I /usr/local/Trolltech/Qt-4.5.1/include/ -L /usr/local/Trolltech/Qt-4.5.1/lib -lQtCore
which removed the compile errors, however when I try to run the program I get this error:
./HelloWorld: error while loading shared libraries: libQtCore.so.4: cannot open shared object file: No such file or directory
I wasn't able to find a solution for this problem via google. Anyone have advice?
That error indicates that while the linker can find the library at compilation, it can't find it during runtime.
You should update your LD_LIBRARY_PATH to include that location like this:
In ~.bashrc probably somewhere near the bottom:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/Trolltech/Qt-4.5.1/lib
Alternatively, if you want to make this persistent throughout your system (and have root access), you can make an entry in /etc/ld.so.conf.d (on RedHat, I'm not sure about the other distributions)
touch /etc/ld.so.conf.d/qt.conf
Add the path to this file, and then update your runtime via /sbin/ldconfig
Related
I'm trying to include the MQTT-C-Client-Library in a simple C++ project.
I have included the header file succesfully like this #include "MQTTClient.h". Compiling it in the linux terminal was printing this errors:
[xy#localhost mosquittoProject]$ sudo g++ *.cpp -o MQTTTest
/tmp/ccHn3s6m.o: In function `main':
mosquitto_test.cpp:(.text+0x11e): undefined reference to `MQTTClient_create'
mosquitto_test.cpp:(.text+0x13f): undefined reference to `MQTTClient_connect'
collect2: error: ld returned 1 exit status
I figured out that I need to link the library after some googling: Example MQTT Client Code not working C
Based on this question and answer I tried compiling it again like this:
sudo g++ -L/home/xy/Desktop/paho.mqtt.c/build/output/ *.cpp -l paho-mqtt3c -o MQTTTest
Which compiles fine but when running I get still an error.
Console commands and output:
[xy#localhost mosquittoProject]$ sudo g++ -L/home/xy/Desktop/paho.mqtt.c/build/output/ *.cpp -l paho-mqtt3c -o MQTTTest
[xy#localhost mosquittoProject]$ ./MQTTTest
./MQTTTest: error while loading shared libraries: libpaho-mqtt3c.so.1: cannot open shared object file: No such file or directory
I replaced the actual username by xy in this post.
What am I doing wrong here?
The problem looks like the library (libpaho-mqtt3c.so.1) is not on the library path.
It looks like you are linking against the build location of the library and have not installed it to the default system location (e.g. /usr/local/lib) by running sudo make install.
By default on Linux the runtime linker searches the locations listed in /etc/ld.so.conf and /etc/ld.so.conf.d. if you edit these remember to run sudo ldconfig to update the cache.
You can add the location of the library to the LD_LIBRARY_PATH environment variable e.g.:
$ LD_LIBRARY_PATH=/home/xy/Desktop/paho.mqtt.c/build/output/ ./MQTTTest
I have written a few programs and while trying to compile them using g++,as thus,
$ g++ minIni.c device_datum.cpp fanuc_axis.cpp fanuc_path.cpp service.cpp condition.cpp cutting_tool.cpp string_buffer.cpp logger.cpp client.cpp server.cpp adapter.cpp fanuc_adapter.cpp FanucAdapter.cpp -L/usr/local/lib/ -lfwlib32 -lpthread -o adapter
I keep getting the following error:
/usr/bin/ld: cannot find -lfwlib32
collect2: error: ld returned 1 exit status
fwlib32.h is the library I am trying to include. The shared object file libfwlib32.so is present in /usr/local/lib as well as /usr/lib. But I am unable link to it. I have tried all the solutions offered by similar questions including
$ export LIBRARY_PATH=/usr/local/lib/
$ export LD_LIBRARY_PATH=/usr/local/lib
I have done the above for /usr/lib as well, but still the same error.
I have tried using the -L option in the command line but I still get the error.
I even created a new folder called lib, pasted libfwlib32.so.1.0.1 into it and ran
$ ln -s ~/lib/libfwlib32.so.1.0.1 ~/lib/libfwlib32.so
on the console to create a new .so file and gave ~/lib as argument to -L option on the command line. It made no difference. I am at the point of tearing my hair out so any help will be appreciated.
Thanks alot!
You should put -l option in the very last as:
$ g++ minIni.c device_datum.cpp fanuc_axis.cpp fanuc_path.cpp service.cpp condition.cpp cutting_tool.cpp string_buffer.cpp logger.cpp client.cpp server.cpp adapter.cpp fanuc_adapter.cpp FanucAdapter.cpp -L/usr/local/lib/ -o adapter -lfwlib32 -lpthread
Note: Please make sure that all the header and source file are in the same folder.
Note that specifying -L~/lib won't work as the ~ will not be expanded by the shell. Also you can't add a space between -L and ~/lib. Instead you must specify it as a relative or absolute path.
Have you checked that the libfwlib32.so symlink exists in /usr/local/lib (or /usr/lib) in addition to the libfwlib32.so.1.0.1 file?
Another possibility is that the library is the wrong architecture (ie. 32-bit while your system is 64-bit), but then ld should print a message about skipping incompatible library. You can check the architecture of the library by running 'file libfwlib32.so.1.0.1'.
The error message suggests that -lfwlib32 is being interpreted as a filename not as a -l parameter. Put all the parameters before the files to be compiled
g++ -m32 -L/usr/local/lib/ -lfwlib32 -lpthread -o adapter minIni.c device_datum.cpp fanuc_axis.cpp fanuc_path.cpp service.cpp condition.cpp cutting_tool.cpp string_buffer.cpp logger.cpp client.cpp server.cpp adapter.cpp fanuc_adapter.cpp FanucAdapter.cpp
As has been pointed out by #Erik Johannessen, libfwlib32.so is a 32bit library, so you need to add -m32 to build a 32bit executable.
I'm currently learning OpenCL. Now, when I want to compile my program, I get an error with this command:
g++ -Wall -l OpenCL main.cpp -o main
The errors are mostly undefined references, because the library is not linked, I think (nevertheless I will post the error code at the end).
But with this command everything works fine:
g++ -Wall main.cpp -o main -l OpenCL
So my question is, what do I have to do, to use the -l Flag in front of the command?
(The Background is: I want to use Netbeans to compile my programm and when i add the flag under -> properties -> build -> C++ Compiler -> additional options, it will put in in the Position, shown in the first command)
Thanks in advance for your help
Here's the error code:
/tmp/ccmKP4oI.o: In function `cl::detail::ReferenceHandler<_cl_context*>::release(_cl_context*)':
main.cpp:(.text._ZN2cl6detail16ReferenceHandlerIP11_cl_contextE7releaseES3_[_ZN2cl6detail16ReferenceHandlerIP11_cl_contextE7releaseES3_]+0x14): undefined reference to `clReleaseContext'
/tmp/ccmKP4oI.o: In function `cl::detail::ReferenceHandler<_cl_command_queue*>::release(_cl_command_queue*)':
main.cpp:(.text._ZN2cl6detail16ReferenceHandlerIP17_cl_command_queueE7releaseES3_[_ZN2cl6detail16ReferenceHandlerIP17_cl_command_queueE7releaseES3_]+0x14): undefined reference to `clReleaseCommandQueue'
/tmp/ccmKP4oI.o: In function `cl::Platform::getInfo(unsigned int, std::string*) const':
main.cpp:(.text._ZNK2cl8Platform7getInfoEjPSs[_ZNK2cl8Platform7getInfoEjPSs]+0x22): undefined reference to `clGetPlatformInfo'
/tmp/ccmKP4oI.o: In function `cl::Platform::get(std::vector<cl::Platform, std::allocator<cl::Platform> >*)':
main.cpp:(.text._ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE[_ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE]+0x41): undefined reference to `clGetPlatformIDs'
main.cpp:(.text._ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE[_ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE]+0xb4): undefined reference to `clGetPlatformIDs'
collect2: error: ld returned 1 exit status
Order of [most] arguments to g++ is very important.
Libraries should go last (at least after source and object files). You can't really change that.
The -l should preferably be glued to the library name:
g++ -Wall main.cpp -o main -lOpenCL
# ^^^ glue the -l to the library name
You probably want to also pass -g (in addition of -Wall) to the compiler to get a debuggable binary. Use the gdb debugger.
As James Kanze commented, you might want to replace -g with -ggdb if using specifically gdb.
With g++ (and generally under Unix), -l specifies a source of
input (either a .a or a .so), and input is processed in
order. When the input is a static library (a .a file), it
will be scanned for objects which resolve undefined references;
if it is a .so, there aren't any object files in it, but it
will still only be taken into consideration if it resolves some
undefined symbol.
When you put the -l before any object files, there are no
undefined symbols yet, so nothing will be incorporated into the
program.
I am trying to use the SDL_ttf development library in an Ubuntu environment. I started by downloading the dev libraries via: sudo apt-get install libsdl-ttf2.0-dev.
Next, I imported the header file in my code as so:
#include <SDL_ttf.h>
When I compile with the command:
g++ -g -I /usr/include/SDL Main.cpp -lSDL -lSDL_image -lSDL_ttf land.cpp PerlinNoise.cpp Util.cpp org.cpp Init.cpp `sdl-config --libs
I get the following output:
/tmp/ccpLKljA.o: In function `init()':
/home/zoo/Desktop/World-A/Util.cpp:39: undefined reference to `TTF_Init'
/home/zoo/Desktop/World-A/Util.cpp:42: undefined reference to `TTF_Quit'
/home/zoo/Desktop/World-A/Util.cpp:48: undefined reference to `TTF_OpenFont'
/home/zoo/Desktop/World-A/Util.cpp:52: undefined reference to `TTF_Quit'
collect2: ld returned 1 exit status
I understand this is a linker error however I do not know what to do to fix it. I know that the -lSDL_ttf command is not doing anything because removing it does not change anything. I tried to reference the .so file however that didn't change the results. I did this reference via the command: -LlibSDL_ttf-2.0.so.0.6.3. I am able to view the .so file and it does contain the commands listed above.
You have to put land.cpp, and the rest of the CPP files, before the libraries on the command line.
Gurus!
I am using Ubuntu 13.10 64-bit to compile latest Google RE2 library, but 'make testinstall' failed to compile, here is the log:
kevin#ubuntu:~/re2$ make testinstall
cp testinstall.cc obj
(cd obj && g++ -I/usr/local/include -L/usr/local/lib testinstall.cc -lre2 -pthread -o testinstall)
/tmp/ccSsaSXS.o: In function main':
testinstall.cc:(.text+0xce): undefined reference tore2::FilteredRE2::FirstMatch(re2::StringPiece const&, std::vector > const&) const'
/usr/local/lib/libre2.so: undefined reference to pthread_rwlock_rdlock'
/usr/local/lib/libre2.so: undefined reference topthread_rwlock_wrlock'
/usr/local/lib/libre2.so: undefined reference to pthread_rwlock_destroy'
/usr/local/lib/libre2.so: undefined reference topthread_rwlock_init'
/usr/local/lib/libre2.so: undefined reference to `pthread_rwlock_unlock'
collect2: error: ld returned 1 exit status
make: * [testinstall] Error 1
I tried to replace -pthread with -lpthread, still failed, then I dumped libre2.so and found that pthread_xxx is in it.
Here is the issue tracking in RE2 forum: https://code.google.com/p/re2/issues/detail?id=100
Anyone here have ever complied RE2 successfully ? Thank you!
See this comment:
Adding -pthread to LDFLAGS seems to fix make test (all tests are
passing), but not make testinstall.
That will get you to the next error
Depending on what you build it for 'make testinstall' might not be necessary.
I just needed to get python re2 port working, and this can be installed after running make install.
I encounter this problem before. Modify the makefile and use -lpthread instead of -pthread.
So I tried looking for the lines in testinstall.cc that were causing the symbol errors and I found out that the only line was on line 18:
18 - f.firstMatch(:abbccc:, ids);
I commented this line out (so that the FullMatch function below is still called) and just ran g++ testinstall.cc -lre2 -pthread -o testinstall (basically what the Makefile does) and I was able to get a binary successfully. Although this might not really solve the problem, its good to know that we can still use the RE2::Fullmatch and partial match functions
If I were to guess, maybe there is a dependency somewhere inside the filtered_re2 module?
I had the same problem. But if you compile with -static everything goes well.
nm -C shows that the "missing" symbol exists in both .a and .so files.