mingw32-make Undefined reference to ...

asked 2019-04-16 10:29:11 -0500

Invidia18 gravatar image

updated 2019-04-16 10:40:33 -0500

So I have OpenCV libraries downloaded from here https://sourceforge.net/projects/open...

CMake gui with cmakelist.txt like this

cmake_minimum_required(VERSION 2.8)


find_package(OpenCV REQUIRED)

message(STATUS "OpenCV library status:") message(STATUS " config: ${OpenCV_DIR}") message(STATUS "
version: ${OpenCV_VERSION}") message(STATUS " libraries: ${OpenCV_LIBS}") message(STATUS "
include path: ${OpenCV_INCLUDE_DIRS}")

add_executable(Display DisplayImage.cpp)

target_link_libraries(Display ${OpenCV_LIBS})

and have a simple cpp like this

#include <stdio.h>
#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

int main(int argc, char** argv )
    // cout << "You have entered " << argc 
 //         << " arguments:" << "\n";

 //        for (int i = 0; i < argc; ++i) 
 //         cout << argv[i] << "\n"; 

 //        cout << "a" << argv[1];
    if ( argc != 2 )
        printf("usage: DisplayImage.out <Image_Path>\n");
        return -1;

    Mat image;
    image = imread( argv[1], 1 );

    if ( !image.data )
        printf("No image data \n");
        return -1;
    namedWindow("Display Image", WINDOW_AUTOSIZE );
    imshow("Display Image", image);

    printf("Hello World!");
    return 0;

already configure it with cmake-gui and this shows up

OpenCV library status: config: D:/opencv/build/x64/vc15/lib version: 3.4.6 libraries: opencv_calib3d;opencv_core;opencv_dnn;opencv_features2d;opencv_flann;opencv_highgui;opencv_imgcodecs;opencv_imgproc;opencv_ml;opencv_objdetect;opencv_photo;opencv_shape;opencv_stitching;opencv_superres;opencv_video;opencv_videoio;opencv_videostab;opencv_world include path: D:/opencv/build/include;D:/opencv/build/include/opencv;D:/opencv/build/include/opencv2 Configuring done Generating done

seems good right ? and then on the build directory from command prompt, i typed mingw32-make and this shows up

CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text+0x72): undefined reference to cv::imread(cv::String const&, int)' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text+0xe3): undefined reference to cv::namedWindow(cv::String const&, int)' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text+0x129): undefined reference to cv::imshow(cv::String const&, cv::_InputArray const&)' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text+0x149): undefined reference to cv::waitKey(int)' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text$_ZN2cv6StringC1EPKc[__ZN2cv6StringC1EPKc]+0x42): undefined reference to cv::String::allocate(unsigned int)' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text$_ZN2cv6StringD1Ev[__ZN2cv6StringD1Ev]+0xf): undefined reference to cv::String::deallocate()' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text$_ZN2cv6StringaSERKS0_[__ZN2cv6StringaSERKS0_]+0x1c): undefined reference to cv::String::deallocate()' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text$_ZN2cv3MatD1Ev[__ZN2cv3MatD1Ev]+0x2d): undefined reference to cv::fastFree(void)' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text$_ZN2cv3Mat7releaseEv[__ZN2cv3Mat7releaseEv]+0x40): undefined reference to cv::Mat::deallocate()' CMakeFiles\Display.dir/objects.a(DisplayImage.cpp.obj):DisplayImage.cpp:(.text$_ZN2cv3MataSEOS0_[__ZN2cv3MataSEOS0_]+0xb4): undefined reference to cv::fastFree(void)' collect2.exe: error: ld returned 1 exit status mingw32-make[2]: * [CMakeFiles\Display.dir\build.make:104: Display.exe] Error 1 mingw32-make[1]: [CMakeFiles\Makefile2:72: CMakeFiles/Display.dir/all] Error 2 mingw32-make: ** [Makefile:83: all] Error 2

how do i fix this ? or is it because that i use the library straight from the ... (more)

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the prebuilt libs from sf are for VS only, you cannot use those with mingw

berak gravatar imageberak ( 2019-04-16 11:46:48 -0500 )edit

do i have to make opencv library for mingw first ? Thanks btw

Invidia18 gravatar imageInvidia18 ( 2019-04-16 15:12:41 -0500 )edit

yes, you have to build the opencv libs from src first. please use the search bar here to find out how.

berak gravatar imageberak ( 2019-04-17 01:23:26 -0500 )edit

so.. i downloaded the library from here https://github.com/huihut/OpenCV-MinG... but when everything is done, it says it needs qt5core.dll and other qt5 dll. why is opencv need qt5 dll ? Thanks again btw, you're really helping

Invidia18 gravatar imageInvidia18 ( 2019-04-17 07:25:26 -0500 )edit

actually i just made my own library using mingw and it worked, but i will still appreciate if u answer my question about the qt part.

big thanks

Invidia18 gravatar imageInvidia18 ( 2019-04-17 11:07:33 -0500 )edit