LNK2019: unresolved external symbol error in Visual Studio C++

Question

This is my code in Visual Studio C++

#include "stdafx.h"
#include<opencv\cv.h>
#include<opencv\highgui.h>

using namespace cv;

int main(int argc, char** argv[]) {
  IplImage* img = cvLoadImage("logo.jpg");
  cvNamedWindow("Test", CV_WINDOW_AUTOSIZE);
  cvShowImage("Test", img);
  cvWaitKey(0);
  cvReleaseImage(&img);
  cvDestroyWindow("Test");
  return 0;
}

I am using OpenCV 2.4.6 and Visual Studio 2010. This is the error:

openCV_testing.obj : error LNK2019: unresolved external symbol _cvDestroyWindow
referenced in function _main
openCV_testing.obj : error LNK2019: unresolved external symbol _cvReleaseImage     
referenced in function _main
openCV_testing.obj : error LNK2019: unresolved external symbol _cvWaitKey referenced in  
function _main
openCV_testing.obj : error LNK2019: unresolved external symbol _cvShowImage referenced   
in function _main
openCV_testing.obj : error LNK2019: unresolved external symbol _cvNamedWindow    
referenced in function _main
openCV_testing.obj : error LNK2019: unresolved external symbol _cvLoadImage referenced 
in function _main

Please help.

Answer 1

'unresolved external symbol' means that you're not linking with required library. Go to Properties -> Linker -> Additional Library dependencies and add path to OpenCV libs.

Answer 2

First check How to build applications with OpenCV inside the Microsoft Visual Studio

If you still suffer from the same problem, you could be under one of the below cases.

1. Your active solution platform is x86 but you are trying to link x64 OpenCV libraries.
2. Your active solution platform is X64 but you are trying to link x86 OpenCV libraries.

If you are under one of these cases, check Compiling a 64-bit Application in Microsoft Visual Studio Express 2010