C++: How to install OpenCV with the compiler MinGW 9.2.0 on Windows 10

Question

I am a few days ago trying to install opencv using Dev-Cpp and Windows 10, i add the directories of the.h, .lib and.dll files to the Dev-Cpp, but when i compile the code always give me the same error.

In compiler options i add the next directories:

-C++ Headers--

C:\Users\admin\Downloads\opencv\build\include

-Libraries-

C:\Users\admin\Downloads\opencv\build\x64\vc15\lib

-Binary files-

C:\Users\admin\Downloads\opencv\build\x64\vc15\bin

-Code-

#include <iostream>
#include <opencv2/imgcodecs.hpp>

int main(){
    cv::Mat img;
    img = cv::imread("Goten.jpg");
    return 0;
}

-Errors-

c:\mingw\mingw32\bin\ld.exe C:\Users\admin\AppData\Local\Temp\cciHfDkS.o:main.cpp:(.text+0x62): undefined reference to `cv::imread(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int)'
c:\mingw\mingw32\bin\ld.exe C:\Users\admin\AppData\Local\Temp\cciHfDkS.o:main.cpp:(.text$_ZN2cv3MatD1Ev[__ZN2cv3MatD1Ev]+0x2d): undefined reference to `cv::fastFree(void*)'
c:\mingw\mingw32\bin\ld.exe C:\Users\admin\AppData\Local\Temp\cciHfDkS.o:main.cpp:(.text$_ZN2cv3Mat7releaseEv[__ZN2cv3Mat7releaseEv]+0x40): undefined reference to `cv::Mat::deallocate()'
c:\mingw\mingw32\bin\ld.exe C:\Users\admin\AppData\Local\Temp\cciHfDkS.o:main.cpp:(.text$_ZN2cv3MataSEOS0_[__ZN2cv3MataSEOS0_]+0xb4): undefined reference to `cv::fastFree(void*)'
C:\Users\admin\Desktop\Programacion\collect2.exe    [Error] ld returned 1 exit status

I have installed MinGW 9.2.0, i tried compile it with the standards C++11, C++14 and C++17

What can i do to fix this error? - Sorry for my english

Answer 1

Those are linker errors: it means the compiler can't find the binary code for those functions.

In other words, you might have forgotten to specify a few OpenCV libraries. If I'm not mistaken, imread() resides in opencv_imgcodecs .

Answer 2

Does vcpkg on Windows require VisualStudio, or does it also work with MinGW? (Doing a very quick Google search seems to show it might work.) Cause ever since I discovered vcpkg , I must admit that I'd never go back to installing and building things the old way.

Now, to get almost anything on windows, I'd clone the vcpkg repo , run the bootstrap script, and then run vcpkg.exe install opencv .

Answer 3

Consider using a good source code editor (perhaps GNU emacs ) and compile on the command line (eg by using a build automation tool such as GNU make or ninja ) in a terminal emulator.

Then MinGW is actually some command with g++ or g++.exe

Then you just can download the source code of OpenCV and compile it in some terminal emulator. Or even better, get the source code from github . The compilation of OpenCV from source code could last a dozen of minutes or an hour of computer time/

BTW, if you really are interested in programming OpenCV, I recommend installing a Linux distribution (eg Debian ). Most GNU/Linux systems have a genuine and recent GCC , not just an emulation of GCC called MinGW.