OpenCV 2.3 doesn't compile, undefined reference error - c++

Question

I'm using OpenCV in Windows 7 64bits and Netbeans 7.0. I tried to compile the next code using MinGW and cygwin but both fails with undefined references.
When I use MAT or FLANN and others I can't compile, but I'm adding all libraries (I tried only adding Debug ones, Release ones, only needed ones... but fails).
The same code in ubuntu works, but I need to compile it in windows too. I'm using the 2.3 compiled version (using CMake) and the installable one.
#include "opencv2\opencv.hpp"
#include <iostream>
using namespace std;
int main(void)
{
cv::Mat::eye(1, 1, 0);
return 0;
}
"/usr/bin/make" -f nbproject/Makefile-Release.mk QMAKE= SUBPROJECTS= .clean-conf
make[1]: Entering directory `/cygdrive/f/Proyectos/C++/OpenCV23Sandbox'
rm -f -r build/Release
rm -f dist/Release/Cygwin-Windows/opencv23sandbox.exe
make[1]: Leaving directory `/cygdrive/f/Proyectos/C++/OpenCV23Sandbox'
CLEAN SUCCESSFUL (total time: 1s)
"/usr/bin/make" -f nbproject/Makefile-Release.mk QMAKE= SUBPROJECTS= .build-conf
make[1]: Entering directory `/cygdrive/f/Proyectos/C++/OpenCV23Sandbox'
"/usr/bin/make" -f nbproject/Makefile-Release.mk dist/Release/Cygwin-Windows/opencv23sandbox.exe
make[2]: Entering directory `/cygdrive/f/Proyectos/C++/OpenCV23Sandbox'
mkdir -p build/Release/Cygwin-Windows
rm -f build/Release/Cygwin-Windows/main.o.d
g++.exe -c -O2 -I/cygdrive/C/OpenCV2.3/build/include -MMD -MP -MF build/Release/Cygwin-Windows/main.o.d -o build/Release/Cygwin-Windows/main.o main.cpp
mkdir -p dist/Release/Cygwin-Windows
g++.exe -o dist/Release/Cygwin-Windows/opencv23sandbox build/Release/Cygwin-Windows/main.o -L/cygdrive/C/OpenCV2.3/build/x86/vc10/lib -lopencv_calib3d230 -lopencv_calib3d230d -lopencv_contrib230 -lopencv_contrib230d -lopencv_core230 -lopencv_core230d -lopencv_features2d230 -lopencv_features2d230d -lopencv_flann230 -lopencv_flann230d -lopencv_gpu230 -lopencv_gpu230d -lopencv_haartraining_engine -lopencv_haartraining_engined -lopencv_highgui230 -lopencv_highgui230d -lopencv_imgproc230 -lopencv_imgproc230d -lopencv_legacy230 -lopencv_legacy230d -lopencv_ml230 -lopencv_ml230d -lopencv_objdetect230 -lopencv_objdetect230d -lopencv_video230 -lopencv_video230d
build/Release/Cygwin-Windows/main.o:main.cpp:(.text+0xac): undefined reference to `cv::Mat::eye(int, int, int)'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text+0x106): undefined reference to `cv::fastFree(void*)'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text+0x16f): undefined reference to `cv::fastFree(void*)'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text+0x1dd): undefined reference to `cv::fastFree(void*)'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text+0x1fa): undefined reference to `cv::Mat::deallocate()'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text+0x20a): undefined reference to `cv::Mat::deallocate()'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text+0x21a): undefined reference to `cv::Mat::deallocate()'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text$_ZN2cv3MatD1Ev[cv::Mat::~Mat()]+0x66): undefined reference to `cv::Mat::deallocate()'
build/Release/Cygwin-Windows/main.o:main.cpp:(.text$_ZN2cv3MatD1Ev[cv::Mat::~Mat()]+0x5e): undefined reference to `cv::fastFree(void*)'
collect2: ld returned 1make[2]: Leaving directory `/cygdrive/f/Proyectos/C++/OpenCV23Sandbox'
make[1]: Leaving directory `/cygdrive/f/Proyectos/C++/OpenCV23Sandbox'
exit status
make[2]: *** [dist/Release/Cygwin-Windows/opencv23sandbox.exe] Error 1
make[1]: *** [.build-conf] Error 2
make: *** [.build-impl] Error 2
BUILD FAILED (exit value 2, total time: 2s)
Trying with MinGW libs:
"/bin/make" -f nbproject/Makefile-Release.mk QMAKE= SUBPROJECTS= .clean-conf
make[1]: Entering directory `/f/Proyectos/C++/OpenCV23Sandbox'
rm -f -r build/Release
rm -f dist/Release/MinGW-Windows/opencv23sandbox.exe
make[1]: Leaving directory `/f/Proyectos/C++/OpenCV23Sandbox'
CLEAN SUCCESSFUL (total time: 350ms)
"/bin/make" -f nbproject/Makefile-Release.mk QMAKE= SUBPROJECTS= .build-conf
make[1]: Entering directory `/f/Proyectos/C++/OpenCV23Sandbox'
"/bin/make" -f nbproject/Makefile-Release.mk dist/Release/MinGW-Windows/opencv23sandbox.exe
make[2]: Entering directory `/f/Proyectos/C++/OpenCV23Sandbox'
mkdir -p build/Release/MinGW-Windows
rm -f build/Release/MinGW-Windows/main.o.d
g++.exe -c -O2 -I/C/OpenCV2.3/build/include -MMD -MP -MF build/Release/MinGW-Windows/main.o.d -o build/Release/MinGW-Windows/main.o main.cpp
mkdir -p dist/Release/MinGW-Windows
g++.exe -o dist/Release/MinGW-Windows/opencv23sandbox build/Release/MinGW-Windows/main.o -L../OpenCV/OpenCV2.3/build/x86/mingw/lib ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_calib3d230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_contrib230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_core230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_features2d230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_flann230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_gpu230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_highgui230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_imgproc230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_legacy230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_ml230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_objdetect230.dll.a ../OpenCV/OpenCV2.3/build/x86/mingw/lib/libopencv_video230.dll.a
build/Release/MinGW-Windows/main.o:main.cpp:(.text+0x4f): undefined reference to `cv::Mat::eye(int, int, int)'
build/Release/MinGW-Windows/main.o:main.cpp:(.text+0xac): undefined reference to `cv::fastFree(void*)'
build/Release/MinGW-Windows/main.o:main.cpp:(.text+0x11a): undefined reference to `cv::fastFree(void*)'
build/Release/MinGW-Windows/main.o:main.cpp:(.text+0x191): undefined reference to `cv::fastFree(void*)'
build/Release/MinGW-Windows/main.o:main.cpp:(.text+0x1a7): undefined reference to `cv::Mat::deallocate()'
build/Release/MinGW-Windows/main.o:main.cpp:(.text+0x1ba): undefined reference to `cv::Mat::deallocate()'
build/Release/MinGW-Windows/main.o:main.cpp:(.text+0x1ce): undefined reference to `cv::Mat::deallocate()'
build/Release/MinGW-Windows/main.o:main.cpp:(.text$_ZN2cv3MatD1Ev[cv::Mat::~Mat()]+0x74): undefined reference to `cv::Mat::deallocate()'
build/Release/MinGW-Windows/main.o:main.cpp:(.text$_ZN2cv3MatD1Ev[cv::Mat::~Mat()]+0x63): undefined reference to `cv::fastFree(void*)'
collect2: ld returned 1 exit status
make[2]: Leaving directory `/f/Proyectos/C++/OpenCV23Sandbox'
make[1]: Leaving directory `/f/Proyectos/C++/OpenCV23Sandbox'
make[2]: *** [dist/Release/MinGW-Windows/opencv23sandbox.exe] Error 1
make[1]: *** [.build-conf] Error 2
make: *** [.build-impl] Error 2
BUILD FAILED (exit value 2, total time: 1s)
or
g++.exe -o dist/Release/MinGW-Windows/opencv23sandbox build/Release/MinGW-Windows/main.o -L../OpenCV/OpenCV2.3/build/x86/mingw/lib -lopencv_calib3d230.dll -lopencv_contrib230.dll -lopencv_core230.dll -lopencv_features2d230.dll -lopencv_flann230.dll -lopencv_gpu230.dll -lopencv_highgui230.dll -lopencv_imgproc230.dll -lopencv_legacy230.dll -lopencv_ml230.dll -lopencv_objdetect230.dll -lopencv_video230.dll
same result.

Answer 1

Are you using the precompiled MinGW libraries? (it appears so). I tried for a couple of days to get my project to link successfully under Code::Blocks. I was seeing the same sort of errors you describe (bad references, etc).
I finally recompiled OpenCV using the steps shown here, and all became well.

Answer 2

I guess the Problem is that the library path points to the vc10 directory (-L/cygdrive/C/OpenCV2.3/build/x86/vc10/lib) instead of the mingw directory (-L/cygdrive/C/OpenCV2.3/build/x86/mingw/lib). The ld-linker can't find the methods because they are mangled for the vc++ "link.exe".
If you use 64 bit, then you have also link against 64-bit libs:
-L/cygdrive/C/OpenCV2.3/build/x64/mingw/lib.

Answer 3

I have exactly the same issue. I am trying to compile my program under a 64-bit Windows 7 machine with MinGW. Here is several possibilities that may result in the problem:
1) You need to make sure OpenCV2.3/build/x64/mingw/lib is link. Be careful, don't link the project to the libs for visual studio or libs for x86.
2) Make sure the proper dlls are copied to the project directory, or have been added to PATH. For example, if you use this lib libopencv_core243.dll.a, you should make sure libopencv_core243.dll can be loaded by the project. This is not the cause of the problem. But I think it is also important to know.
3) Make sure the MinGW can compile x64 programs. This is what I use: mingw-w64 (But since mingw-w64 project is moving to mingw-w64.org it's better to use the new website). Unfortunately, the one that download from MinGW32 won't work. And the link from the official site of MinGW will bring you to a second one (MinGW32).
4) By default, MinGw may compile your project to a 32 bit program. In order to make sure it compiles for 64 bit, add this compile flag -m64. Otherwise, if you only link the project with all the 64-bit libs, it will result in the problem as well.