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installed Opencv 4 from source, C++ headers not linked correctly

asked 2019-08-16 17:14:21 -0500

mjxlyons gravatar image

I jusst installed Opencv 4.1.1 from source, with python 3 bindings. My Python installation seems to work correctly, because if I run:

import cv2

I get '4.1.1'

However, I also want to use some C++ code. I had a previous installation of 3.4.3 that I built from source, and unfortunately I had deleted the build folder before uninstalling it. So, when I run this C++ code:

#include <opencv4/opencv2/core.hpp>

using namespace cv;
using namespace std;
int main( int argc, char** argv )
    //print opencv version
    printf("opencv version: %d.%d.%d\n",CV_VERSION_MAJOR,CV_VERSION_MINOR,CV_VERSION_REVISION);

    return 0;

When i compile with this command :

g++ -o get_version get_version.cpp -I/usr/local/include/opencv4/opencv2 -Lusr/local/lib -lopencv_core

It returned 3.4.3.

So, I wanted to fix this, so I found the old header files, and deleted them all (they were located in /usr/local/include/opencv2). But now when I try to compile my code, it gives me the error:

In file included from get_version.cpp:1:0:
/usr/local/include/opencv4/opencv2/core.hpp:52:10: fatal error: opencv2/core/cvdef.h: No such file or directory
 #include "opencv2/core/cvdef.h"
compilation terminated.

But, if I navigate to /usr/local/include/opencv4/opencv2/core/, I can see the file, cvdef.h, so I don't know why the compiler can't find it.

So, why are my headers not linking correctly? And how can I fix this. I'm used to Python, so I'm I'm not used to having to deal with linking all these header files, so sorry if it's something obvious.

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how do you try to compile the c++code (please add that to your question, thank you)

berak gravatar imageberak ( 2019-08-17 00:29:43 -0500 )edit

Using a virtual environment for different setups can solve a lot of problems :D Or docker containers. Its an easy way to avoid conflicts between versions without breaking up the host system.

StevenPuttemans gravatar imageStevenPuttemans ( 2019-08-19 09:01:27 -0500 )edit

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answered 2019-11-10 14:30:33 -0500

You can use CMAKE method for compiling the code. In CMakeLists.txt, under find_package command, you can specify the exact library version you want to use for compilation. For example.

cmake_minimum_required(VERSION 2.8)

project( DisplayImage )

find_package( OpenCV 4.1.2 REQUIRED )

include_directories( ${OpenCV_INCLUDE_DIRS} )

add_executable( DisplayImage main.cpp )

target_link_libraries( DisplayImage ${OpenCV_LIBS} )

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Asked: 2019-08-16 17:14:21 -0500

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Last updated: Aug 16 '19