I'm trying to compile a program i made using SDL2 to work on others computers (or testing VM in this case).
I've been compiling it with what i think are the correct flags, e.g. g++ main.cpp -o main -lSDL2, however when i try executing it on another Ubuntu installation i get this error.
error while loading shared libraries: libSDL2-2.0.so.0: cannot open shared object file: No such file or directory
From my understanding it's not a problem in my compiling but with how i expect it to work on another Linux installation; I've cross-compiled (using mingw32) and tested it (using a freshly installed VM) on Windows adding the correct dlls with the exe (seems to work fine) and I was expecting for it to work in a similar fashion.
What's the standard in this cases? Should i write a setup scripts to install the library dependencies on the target machine? Is there another way I'm not aware of? I've never released an application for Linux (nor Windows) and I'm struggling to find the resources to do things "the right way".
Thanks for everyone suggestions, I ended up settling for the easy way, compiling the "easy to install" libraries dynamically e.g.-lSDL2 and the others statically (checked the licenses and it should be fine) like so:
g++ main.cpp -o main -Wl,-Bdynamic -lSDL2 -lSDL2_image -lSDL2_ttf -Wl,-Bstatic -lSDL2_gfx -static-libgcc -static-libstdc++
I'll put in my documentation how to install the required SDL2 libraries.
I am not sure how familiar you are with pkg-config, but the output for sdl2 is this:
-D_REENTRANT -I/usr/include/SDL2 -lSDL2
This was found from running this:
pkg-config --cflags --libs sdl2
Basically, you need to point to where SDL2 is located BEFORE you actually link to it.
The tool pkg-config is designed to tell you the information you need when you want to link to a package in Linux. You were linking with the library, but you forgot to tell GCC where the library is located.
If you want to compile you code, try this:
g++ main.cpp -o runme `pkg-config --cflags --libs sdl2`
This will automatically grab all of the flags that you need to compile with SDL2 included.
Oh, and you should note, ORDER MATTERS WHEN ADDING FLAGS AND LIBRARIES!!!
There are many questions on SO where the order of compiler options caused all of the problems. Do not be like those people. I suggest you search SO for more info on that.
Related
I am new to the Point Cloud Library. There is a thing that has been bugging me for some time.
So, on my system, whenever I have to compile a C++ program, which requires OpenCV libraries to be linked, I use the following terminal command:
g++ -std=c++11 fileName.cpp -o executableFile `pkg-config --cflags --libs opencv`
Now, things have turned to a point where I have to use PCL. But, everywhere (including the PCL's official website) people link PCL libraries using a CMake file, and I am not familiar with CMake.
Is there a way to include the PCL libraries without writing a CMake file and just including some more flags/parameters to the terminal command?
I am using Ubuntu 18.04.
I experimented for a while, and here is how I figured this out.
man pkg-config tells you the folders where pkg-config looks for .pc files. So, I checked those folders for the exact .pc file names that I want pkg-config to link with my .cpp file. I found the required file (pcl_io-1.11.pc) at \usr\local\lib\pkgconfig
Next, I modified my terminal command to the following (please consider two back-quotes as a single back-quote below)
g++ -std=c++14 pcd_write.cpp -o pcd_write ``pkg-config --cflags --libs pcl_io-1.11`` -lboost_system
Note: Not including the -lboost_system would result in another error message. I found this helpful.
This compiled successfully. But, on running the executable, I would get this error message:
./pcd_write:error while loading shared libraries:libpcl_io.so.1.11:cannot open shared object file:No such file or directory
The solution to this problem was found here
sudo /sbin/ldconfig -v
Then, running the executable gave the expected results.
I'm creating a game in c++ with the Panda3D framework on Ubuntu. All of the Panda3D shared libraries are in /usr/lib/panda3d and all of the headers are in /usr/include/panda3d. I'm compiling with SCons, but I've tried it with gcc and it's the same, so here are the commands:
g++ -o src/main.o -c -fPIC -O2 -std=gnu++11 -I/usr/include/python2.7 -I/usr/include/panda3d -Iinclude src/main.cpp
g++ -o Test src/main.o -L/usr/lib/panda3d -lp3framework -lpanda -lpandafx -lpandaexpress -lpandabullet -lp3dtoolconfig -lp3dtool -lp3direct -lpthread
And here is the error I get when I run the executable:
./Test: error while loading shared libraries: libp3framework.so.1.11: cannot open shared object file: No such file or directory
There isn't much in the code, just initializing a Panda3D window, so I doubt that's the culprit.
As I said before, the libraries are in /usr/lib/panda3d, I've checked about a million times now and it's driving me crazy. I can't think of a single reason why I would get this error. Any help is appreciated :)
Edit:
I was looking through my files and there's a panda3d.conf file in /etc/ld.so.conf.d with one line: /usr/local/lib/x86_64-linux-gnu/panda3d. Does this have anything to do with it?
Edit #2:
I used the path in the above edit as the library path and got the same results, unfortunately.
I can't think of a single reason why I would get this error.
The reason is very simple: the dynamic loader hasn't been told to look in /usr/lib/panda3d for shared libraries, and so doesn't.
You can run your program with:
LD_DEBUG=files,libs ./Test
and observe which directories the loader is searching.
panda3d.conf ... with one line: /usr/local/lib/x86_64-linux-gnu/panda3d
That is the wrong directory (or at least not the one where your libraries are).
One way to fix this is to correct the above path to /usr/lib/panda3d and run sudo ldconfig.
Another way is to add -Wl,-rpath=/usr/lib/panda3d to your link line.
I'm working on a project on a Raspberry Pi 2 Model B. I started coding and compiling directly on the Pi and now I want to work on a Windows 7 PC. I already installed the SysGCC Cross-Compiler and managed to compile a simple Hello-World program.
Problem is, for my Project i use curl and jsoncpp. Natively on the Raspberry i have no problems compiling it, but the cross-compiler on Windows gives me following error:
c:/sysgcc/raspberry/bin/../lib/gcc/arm-linux-gnueabihf/6/../../../../arm-linux-gnueabihf/bin/ld.exe: cannot find -lcurl
c:/sysgcc/raspberry/bin/../lib/gcc/arm-linux-gnueabihf/6/../../../../arm-linux-gnueabihf/bin/ld.exe: cannot find -ljsoncpp
I don't use a makefile or so because i never really worked with that and on the raspi it just worked fine with this command:
g++ ../src/rpi/main.cpp ../src/rpi/connection.cpp ../src/rpi/jsonparser.cpp ../src/rpi/idchecker.cpp ../src/rpi/eventoperator.cpp -o ../bin/main -lcurl -ljsoncpp
On the Windows system i tried it with a command like this:
arm-linux-gnueabihf-g++.exe -std=c++11 ../src/rpi/main.cpp ../src/rpi/connection.cpp ../src/rpi/jsonparser.cpp ../src/rpi/idchecker.cpp ../src/rpi/eventoperator.cpp -o ../bin/main -L"C:/SysGCC/raspberry/arm-linux-gnueabihf/sysroot/usr/include/jsoncpp/json/" -L"C:/SysGCC/raspberry/arm-linux-gnueabihf/sysroot/usr/include/arm-linux-gnueabihf/curl/" -lcurl -ljsoncpp
So i read that i have to tell the compiler/linker where the libraries are, but i don't really understand why since it works perfectly without the -L flag on the Raspi. I think i put the libraries in the same folder as on the Raspi, so i don't understand why they are not found. I hope someone can help me ore give me some short basic explanation on how this stuff works, cause i don't find any working tutorial or other helpful questions for my problem.
On raspberry-pi the libraries are most likely to be linked from system directory like /usr/lib or /usr/local/lib. On Windows, you need to specify the correct path(s) with -L flag.
I have built a GCC cross toolchain for the RPi and can cross-compile C++ source and successfully run it after copying the executable to the RPi.
Next I built the Boost libraries targeting ARM, using the cross toolchain. I can successfully build and link C++ source to those Boost libraries using the cross toolchain on my PC.
I then copied the program, dynamically linked to Boost, to the RPi and copied all built libraries into /usr/local/lib on the Pi. However, executing fails:
$ ./my_program
./my_program: error while loading shared libraries: libboost_system.so.1.60.0: cannot open shared object file: No such file or directory
Again, this library, libboost_system.so.1.60.0, exists in /usr/local/lib.
I also tried
export LD_LIBRARY_PATH='/usr/local/lib'
but that doesn't change anything. What am I doing wrong?
EDIT:
I build all source files like this (rpi-g++ is a symlink to my cross-compiler):
rpi-g++ -c -std=c++1y -Wall -Wextra -pedantic -O2 -I /path/to/cross/boost/include *.cpp
rpi-g++ -o myprog *.o -L /path/to/cross/boost/lib/ -lboost_system -pthread
EDIT 2:
When linked with
rpi-g++ -o myprog *.o -L /path/to/cross/boost/lib/ -rdynamic -lboost_system -pthread
the problem remains the same. I have checked and verified everything suggested by Technaton as well. Strangely, ldd insists that the created executable is "not a dynamic executable" (checked that on my PC and on the RPi), which doesn't make sense to me.
There are several things you can check. I've posted a complete check list here, but judging from your linker command line, number 5 is probably the culprit.
Check that your library and your program are correctly build for the target architecture. You can verify that by using file ./myprog and file libboost_system.so.1.60.0.
Make sure that you have copied the actual shared object, and not a link to it.
Ensure that the shared object file's permissions are sane (0755).
Run ldconfig -v and check that your shared object file is picked up. Normally, /usr/local/lib is in the standard library search path, and LD_LIBRARY_PATH is not required.
Make sure that your program is actually dynamically linked by running ldd ./myprog. Judging from your linker command line, that is the problem: You're missing -rdynamic.
Check the paths returned from ldd: If you have linked with rpath, the library search path might be screwed up. Try again without -rpath.
I'm trying to compile code using SDL, I can't really post much of the code here but I can do my best to answer questions about it. The problem occurs when compiling the view code and trying to link the SDL libraries.
g++ -o test test.c -lSDL2main -lSDL2
gives me an error /usr/bin/ld: cannot find -lSDL2main
I know my SDL install is okay because if I leave out the link to SDL2main it compiles fine and runs fine. The problem is there is other code that needs SDL2main. I've poured through my file system and I can't find it and I've searched online pretty exhaustively. I was just hoping someone could help me either resolve the dependency or fix my sdl install if its broken.
If you are using some distro there's probably some tool to search files, even in packages not installed.
For example (I'm using Debian/unstable) apt-file search SDL2main
libsdl2-dev: /usr/lib/i386-linux-gnu/libSDL2main.a
libsdl2-2.0-0:i386 2.0.2+dfsg1-4
libsdl2-dev 2.0.2+dfsg1-4
Once you've verified that the lib exist if it doesn't link there still something to check and try
Check the lib is installed in one of the search path (see How to print the ld(linker) search path)
Or explicit the path
g++ -o test test.c -L/usr/lib/i386-linux-gnu -lSDL2main -lSDL2
Being a static library with some gcc/g++/ld version maybe you need to link the archive as an object, without -l
g++ -o test test.c /usr/lib/i386-linux-gnu/libSDL2main.a -lSDL2