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.
Related
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.
I was creating program on windows with SDL2 and the program worked fine, but when I changed my os to linux mint (and install code::blocks, gcc, g++, SDL2), I run into troubles with compiling my code.
I have one error:
- ld||cannot find -lmingw32|
I guess that I don't have mingw32 library, where can I get it? Or is the problem diferent?
BTW: I also tryed to google it.
Thank for response.
Read the manual.
On linux you don't need -lmingw32. Instead, use
`sdl2-config --libs`
to get the list of all needed linker flags.
Example usage:
gcc -o myprogram myprogram.o `sdl2-config --libs`
Problem was solved by removing linker on mingw32 and lib rotozoom.h.
Problem first, then details:
I copied a hello-world program from the wxwidgets tutorials and tried to compile it from the command line like this:
g++ -o h wxhello.cpp -I/usr/include/wx-3.0
The compile terminated quickly because it could not find "wx/setup.h". I researched this apparently EXTREMELY COMMON PROBLEM and learned that there is supposed to be a second include path, pointing to the place where the individual setup.h that suits my situation can be found. So I tried:
find /usr/include/wx-3.0 -name "setup.h"
And the output was nothing.
So I installed wxWidgets by marking libwxgtk3.0-dev in Synaptic and allowing all the dependencies to be installed (something like 40 packages in all because I just set this thing up).
How do I get my program to compile?
You need to have wx-config --cxxflags --libs in your command line enclosed in back-ticks like this
g++ -o h wxhello.cpp `wx-config --cxxflags --libs`
This is not the solution on Windows, but it should work on any Linux.
This is not documented in a searchable fashion as far as I can tell.
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
I'm trying to call R from c++ on linux via RInside, I compiled R-2.15.1 from source with gcc version 4.5.3 (Debian 4.5.3-1) , I don't have sudo rights to use apt-get install. I'm using OpenBlas and a system optimized lapack. The blas and lapack libraries work fine for many scalapack applications
I installed R with
./configure --with-blas="-I/lib/OpenBLAS-v0.2.3-0/xianyi-OpenBLAS-48f075c/install/include -L/lib/OpenBLAS-v0.2.3-0/xianyi-OpenBLAS-48f075c/install/lib -lopenblas -lgfortran" --with-lapack="/usr/lib/liblapack.so -lgfortran" --enable-BLAS-shlib=yes --enable-R-shlib --enable-R-static-lib --prefix= .
which installed and runs fine,I ran make check with no errors, also all the packages (Rcpp and RInside) installed fine..
however when i use the given RInside makefile , the basic hello world example from /standard/rinside_sample0.cpp compiles! but it does not run and i get the following error
./rinside_sample0: error while loading shared libraries: libRblas.so: cannot open shared object file: No such file or directory
the file libRblas.so exists and is in the R/lib folder,
when i try to link it manually with the g++ command the make file creates or linking as follows i get a segmentation fault
/R/lib/libRblas.so ./hello_world
Segmentation fault
EDIT: heres how the example make file tries to compile an example, (which compiles fine) but won't run with the above missing libRblas.so error
g++ -I/nfs/user03/jimmie21/libs/lib64/R/include -I/nfs/user03/jimmie21/libs/lib64/R/library/Rcpp/include -I/nfs/user03/jimmie21/libs/lib64/R/library/RInside/include -g -O2 -Wall -I/usr/local/include hello_world.cpp -L/nfs/user03/jimmie21/libs/lib64/R/lib -lR -L/nfs/user03/jimmie21/libs/lib64/R/lib -lRblas -L/nfs/user03/jimmie21/libs/lib64/R/lib -lRlapack -L/nfs/user03/jimmie21/libs/lib64/R/lib -lRblas -L/nfs/user03/jimmie21/libs/lib64/R/library/Rcpp/lib -lRcpp -Wl,-rpath,/nfs/user03/jimmie21/libs/lib64/R/library/Rcpp/lib -L/nfs/user03/jimmie21/libs/lib64/R/library/RInside/lib -lRInside -Wl,-rpath,/nfs/user03/jimmie21/libs/lib64/R/library/RInside/lib -o hello_world
Couple of things:
Reproducible examples, please
You have a non-standard setup
With the script from 1), try it on a standard setting as that is how Rcpp / RInside get developed and tested (on Ubuntu / Debian)
The Rcpp test suite now contains almost 800 unit tests from around 350 unit test functions. These do not seg.fault, so the issue is at your end. Similarly, RInside has dozens of examples in the four examples/ subdirectories. This also works.
It may be as easy as tweaking the Makefile / Makevars files to make sure you get your libraries in all cases. But we can't tell as there is nothing reproducible here.
Edit If you want to link with libRblas.so then you have a completely non-standard setup as the R packages for Debian / Ubuntu as use the external BLAS. Again, not an RInside issue.
I fixed the problem by adding the R install path lib ../R/lib: to the beginning of LD_LIBRARY_PATH after that all the examples compiled and run fine