I am new to cpp, want to have a implementation of particle filter, I try to run the code here https://github.com/NewProggie/Particle-Filter, which is a structured and easy understanding project. But when I try to compile and link:
g++ $(pkg-config --cflags --libs opencv) -I/usr/local/Cellar/opencv3/3.1.0_1/include -I /usr/local/Cellar/gsl/1.16/include -stdlib=libc++ main.cpp -o main
I have following linking problem:
Undefined symbols for architecture x86_64:
"colorFeatures::colorFeatures()", referenced from:
_main in main-2b4c23.o
"colorFeatures::~colorFeatures()", referenced from:
_main in main-2b4c23.o
"adaboostDetect::detectObject(_IplImage*, CvRect**)", referenced from:
_main in main-2b4c23.o
"adaboostDetect::adaboostDetect()", referenced from:
_main in main-2b4c23.o
"tracker::addObjects(_IplImage*, CvRect*, int)", referenced from:
_main in main-2b4c23.o
"tracker::initTracker(_IplImage*, CvRect*, int, int)", referenced from:
_main in main-2b4c23.o
"tracker::showResults(_IplImage*)", referenced from:
_main in main-2b4c23.o
"tracker::next(_IplImage*)", referenced from:
_main in main-2b4c23.o
"tracker::tracker()", referenced from:
_main in main-2b4c23.o
"tracker::~tracker()", referenced from:
_main in main-2b4c23.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Any kind person has ideas about this problem? Thanks in advance
have gsl installed properly
B) pass to g++ a reference to the lib directory where the gsl libraries are located (probably something like /usr/lib or /usr/local/lib, these should both be default locations for the linker to search), and also to where the header files are, and also tell the linker to do the linking.
g++ -o <name of executable> -L/path/to/gsl/libs -I/path/to/headers -lgsl <name of source file>
the -L tells it where to find the libraries (.so files on linux, .dylib on OS X), -I tells it where to find the headers, -l (that's a lower case L) tells it to link to the library, which would be named libgsl.so or libgsl.dylib.
First just try adding the -lgsl flag, then if it can't find libgsl.so (or .dylib), add the -L flag. NOTE: /path/to/gsl/libs and /path/to/headers are not what you should literally put in there, but replace them with the actual paths on your system.
Related
I'm using gcc(version 11) to compile my .cpp file, and the code is below, which is copied from the official website of ginac.
#include <iostream>
#include <ginac/ginac.h>
using namespace std;
using namespace GiNaC;
int main()
{
symbol x("x"), y("y");
ex poly;
for (int i=0; i<3; ++i)
poly += factorial(i+16)*pow(x,i)*pow(y,2-i);
cout << poly << endl;
return 0;
}
I used the compiling command like this:
gcc-11 -lstdc++ -lginac -lcln hello.cpp -o hello -I /usr/local/include -L /usr/local/lib
After that, I got some errors like this:
Undefined symbols for architecture x86_64:
"__ZN5GiNaC12archive_node6add_exERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERKNS_2exE", referenced from:
__ZNK5GiNaC9containerISt6vectorE7archiveERNS_12archive_nodeE in ccEkVJyo.o
"__ZN5GiNaC5basic12read_archiveERKNS_12archive_nodeERNS_9containerINSt7__cxx114listEEE", referenced from:
__ZN5GiNaC9containerISt6vectorE12read_archiveERKNS_12archive_nodeERNS0_INSt7__cxx114listEEE in ccEkVJyo.o
"__ZN5GiNaC6symbolC1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from:
_main in ccEkVJyo.o
"__ZN5GiNaC9containerISt6vectorE8reg_infoE", referenced from:
__ZN5GiNaC9containerISt6vectorE21get_class_info_staticEv in ccEkVJyo.o
"__ZN5GiNaClsERSoRKNS_2exE", referenced from:
_main in ccEkVJyo.o
"__ZNK5GiNaC12archive_node14find_ex_by_locEN9__gnu_cxx17__normal_iteratorIPKNS0_8propertyESt6vectorIS3_SaIS3_EEEERNS_2exERNS_9containerINSt7__cxx114listEEE", referenced from:
__ZN5GiNaC9containerISt6vectorE12read_archiveERKNS_12archive_nodeERNS0_INSt7__cxx114listEEE in ccEkVJyo.o
"__ZNK5GiNaC12archive_node19find_property_rangeERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES8_", referenced from:
__ZN5GiNaC9containerISt6vectorE12read_archiveERKNS_12archive_nodeERNS0_INSt7__cxx114listEEE in ccEkVJyo.o
"__ZNK5GiNaC5basic10eval_ncmulERKSt6vectorINS_2exESaIS2_EE", referenced from:
__ZTVN5GiNaC9containerISt6vectorEE in ccEkVJyo.o
"__ZNK5GiNaC5basic11to_rationalERSt3mapINS_2exES2_NS_10ex_is_lessESaISt4pairIKS2_S2_EEE", referenced from:
__ZTVN5GiNaC9containerISt6vectorEE in ccEkVJyo.o
"__ZNK5GiNaC5basic13contract_withEN9__gnu_cxx17__normal_iteratorIPNS_2exESt6vectorIS3_SaIS3_EEEES8_RS7_", referenced from:
__ZTVN5GiNaC9containerISt6vectorEE in ccEkVJyo.o
"__ZNK5GiNaC5basic13to_polynomialERSt3mapINS_2exES2_NS_10ex_is_lessESaISt4pairIKS2_S2_EEE", referenced from:
__ZTVN5GiNaC9containerISt6vectorEE in ccEkVJyo.o
"__ZNK5GiNaC5basic14subs_one_levelERKSt3mapINS_2exES2_NS_10ex_is_lessESaISt4pairIKS2_S2_EEEj", referenced from:
__ZNK5GiNaC9containerISt6vectorE4subsERKSt3mapINS_2exES4_NS_10ex_is_lessESaISt4pairIKS4_S4_EEEj in ccEkVJyo.o
"__ZNK5GiNaC5basic5matchERKNS_2exERSt3mapIS1_S1_NS_10ex_is_lessESaISt4pairIS2_S1_EEE", referenced from:
__ZTVN5GiNaC9containerISt6vectorEE in ccEkVJyo.o
"__ZNK5GiNaC5basic6normalERSt3mapINS_2exES2_NS_10ex_is_lessESaISt4pairIKS2_S2_EEES9_RNS_9containerINSt7__cxx114listEEE", referenced from:
__ZTVN5GiNaC9containerISt6vectorEE in ccEkVJyo.o
"__ZNK5GiNaC9containerISt6vectorE4infoEj", referenced from:
__ZTVN5GiNaC9containerISt6vectorEE in ccEkVJyo.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status
I know that Undefined Symbols error often comes up because of the link error, but the detailed error messages looks like that these errors are from ginac itself.
I have tried different orders of these -l parameters, but the errors always exist.
I tried clang instead of gcc to compile this file and it works. So I guess I do install the ginac library correctly. But I'm still confused about these errors when using gcc.
Has anyone met this problem?
I would be very appreciate if anyone could give me some advice!
I also had issues using:
gcc-11 -lstdc++ -lginac -lcln hello.cpp -o hello -I /usr/local/include -L /usr/local/lib
but it did work with:
g++ -o hello hello.cpp `pkg-config --cflags --libs ginac`
This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 2 years ago.
I'm trying to compile using SDL2 library with no success.
OS: MacOS 10.13.2
Visual Studio Code 1.43.1
Language: c++
I'm using the Lazy Foo's very basic example code.
This is the message I recieve:
[Running] cd "/Users/martinjoselizondocolomes/Programacion/01_hello_SDL/" && g++ 01_hello_SDL.cpp -o 01_hello_SDL && "/Users/martinjoselizondocolomes/Programacion/01_hello_SDL/"01_hello_SDL
Undefined symbols for architecture x86_64:
"_SDL_CreateWindow", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_Delay", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_DestroyWindow", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_FillRect", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_GetError", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_GetWindowSurface", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_Init", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_MapRGB", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_Quit", referenced from:
_main in 01_hello_SDL-a16d96.o
"_SDL_UpdateWindowSurface", referenced from:
_main in 01_hello_SDL-a16d96.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
[Done] exited with code=1 in 0.168 seconds
Building C++ code requires three stages:
Preprocessor deals with macros and #include directives, so your header files are required at this step.
Compiler generates object files. This is the point when the syntax is checked in your source files.
Linker combines object files and libraries into an executable so your runtime libraries must be available and specified to the linker.
For g++, you specify libraries by giving their full name on the command line or use the -l shortcut which figures out the proper prefix (lib) and suffix. So in your case I believe you can add -lSDL.
EDIT: If that doesn't work, check the output of
sdl-config --libs
$clang++ main.cpp -o out
Got following error, the same error happens when changing to g++. I have tested on some simple simple c++ code, the command works fine. So it the problem in that PNG class file? However, the same files worked on my MacOS before, but suddenly failed today.
Undefined symbols for architecture x86_64:
"PNG::writeToFile(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
_main in main-f6a06a.o
"PNG::PNG(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
_main in main-f6a06a.o
"PNG::PNG(unsigned long, unsigned long)", referenced from:
_main in main-f6a06a.o
"PNG::~PNG()", referenced from:
_main in main-f6a06a.o
"PNG::operator()(unsigned long, unsigned long)", referenced from:
_main in main-f6a06a.o
"PNG::width() const", referenced from:
_main in main-f6a06a.o
"PNG::height() const", referenced from:
_main in main-f6a06a.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Did you miss providing static/shared to the linker to resolve the linker errors for the methods mentioned? Also note that clang++ is a different compiler compared to g++ and hence need the static/shared libraries compiled prior by the same compiler you are using (clang++).
Try:
clang++ main.cpp -o out -lpng
Here's why: You are not providing the library that contains the implementation of your PNG library (libpng most likely). You need -lpng added to your compiler, so that it links with the relevant library. It may not be exactly -lpng in your particular case, but it's definitely a "missing library". Without knowing exactly what library you are trying to use (you didn't provide some source to "try the fix with").
As pointed out in the comment: you are using some kind of C++ wrapper on top, the above is probably not enough - but without knowing exactly which C++ wrapper on the png functionality you are actually using, it's hard to say what the command-line should look like.
Perhaps this
This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 7 years ago.
I am using OpenCV to record the video from webcam. I used Xcode 6.4 to write a (C++) code to record the video on OS X Yosemite 10.10.4. It is working perfectly fine when I compile and run it from Xcode but when I want to compile (using g++ -o main main.cpp) it from terminal it generates following errors:
Undefined symbols for architecture x86_64:
"cv::VideoWriter::write(cv::Mat const&)", referenced from:
_main in main-027833.o
"cv::VideoWriter::VideoWriter(cv::String const&, int, double, cv::Size_<int>, bool)", referenced from:
_main in main-027833.o
"cv::VideoWriter::~VideoWriter()", referenced from:
_main in main-027833.o
"cv::VideoCapture::VideoCapture(int)", referenced from:
_main in main-027833.o
"cv::VideoCapture::~VideoCapture()", referenced from:
_main in main-027833.o
"cv::VideoCapture::operator>>(cv::Mat&)", referenced from:
_main in main-027833.o
"cv::Mat::deallocate()", referenced from:
cv::Mat::release() in main-027833.o
"cv::String::deallocate()", referenced from:
cv::String::~String() in main-027833.o
"cv::String::allocate(unsigned long)", referenced from:
cv::String::String(char const*) in main-027833.o
"cv::imshow(cv::String const&, cv::_InputArray const&)", referenced from:
_main in main-027833.o
"cv::waitKey(int)", referenced from:
_main in main-027833.o
"cv::fastFree(void*)", referenced from:
cv::Mat::~Mat() in main-027833.o
"cv::VideoCapture::get(int) const", referenced from:
_main in main-027833.o
"cv::VideoCapture::isOpened() const", referenced from:
_main in main-027833.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command fail
ed with exit code 1 (use -v to see invocation)
I know its because it can't link OpenCV lib. I tried using "vi
$HOME/.bash_profile" and then setting path like
"export PATH=$PATH:/usr/local/include"
and
"export PATH=$PATH:/user/local/lib"
but it doesn't help. Also I tried
g++ -o main main.cpp -l `pkg-config opencv --cflags --libs`
but of no use.
I don't know how to specify path. Any help would be appreciated.
Thanks!
Finally, after 3 days of frustration I found the solution. I am sharing for someone who is also struggling with the same kind of problem.
What you have to do is just add all those flags that you added in the Xcode "other linker flags" while compiling your code from terminal. So here is the command that works for me.
g++ main.cpp -o main -I/usr/local/include -L/usr/local/lib -lopencv_core -lopencv_calib3d -lopencv_videoio -lopencv_video -lopencv_videostab -lopencv_highgui
I didn't include all the flags because I was only working with videos but you may have to add more or less depending on what you are working on.
I have compiled libFLAC from source code under macintosh os x 10.6.8 and tested WAV to FLAC conversion with success (from the command line). I have also used the default build as such: ./configure --prefix="$base/flac/more/" --exec-prefix="$base/flac/main/" --disable-asm-optimizations && make && make install
Now after adding the paths for FLAC headers and the libs into a brand new project. I am attempting to decode and load FLAC audio into system memory using libFLAC, under the example code which was bundled with libFLAC. However i am getting symbols not found errors with Standard C and vtable symbols not found errors with the Standard C++ approach (as seen below).
Errors under the C approach:
"FLAC_stream_decoder_get_state", referenced from:
_main in main.o
"FLAC_stream_decoder_new", referenced from:
_main in main.o
"FLAC_StreamDecoderStateString", referenced from:
_main in main.o
"FLAC_StreamDecoderErrorStatusString", referenced from:
error_callback(FLAC__StreamDecoder const*,
FLAC__StreamDecoderErrorStatus, void*)in main.o
"FLAC_stream_decoder_init_file", referenced from:
_main in main.o
"FLAC_StreamDecoderInitStatusString", referenced from:
_main in main.o
"FLAC_stream_decoder_set_md5_checking", referenced from:
_main in main.o
"FLAC_stream_decoder_process_until_end_of_stream", referenced from:
_main in main.o
"FLAC_stream_decoder_delete", referenced from:
_main in main.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
From what i can understand is either: the linker is not seeing the libs (because it is seeing the headers) or the libFLAC was not compiled correctly. I'll be thankful if anyone will point me to possible solutions given these errors.
I was doing the linking incorrectly. Linking needs to be done according to this stackoverflow post Adding static library inside Xcode C++ project (How to add static libraries inside a C++ project with Xcode) but i was adding the linking directory under the Project Setting where i was adding my headers path, thus it was not working.