Compiling Programs in OpenCV

Question

I'm just starting with OpenCV and am stuck running the sample code on this website.

I made a .cpp file and copy/pasted the code in.

I ran the following command on the command line:

g++ program.cpp -o program

I got the following errors:

undefined reference to `cv::imread(cv::String const&, int)'

program.cpp:(.text+0x128): undefined reference to `cv::namedWindow(cv::String const&, int)'

program.cpp:(.text+0x17d): undefined reference to `cv::imshow(cv::String const&, cv::_InputArray const&)'

program.cpp:(.text+0x1a5): undefined reference to `cv::waitKey(int)'

/tmp/cceJEar6.o: In function `cv::String::String(char const*)':

program.cpp:(.text._ZN2cv6StringC2EPKc[_ZN2cv6StringC5EPKc]+0x4d): undefined reference to `cv::String::allocate(unsigned long)'

It seems to be a linking problem where it can't find the cv namespace or the opencv libraries

Noob Coder · Accepted Answer · 2016-06-07 05:49:16Z

4

You haven't specified the OpenCV libraries while compiling. Use this command:

g++ `pkg-config --cflags opencv` codename.cpp `pkg-config --libs opencv` -o codename

answered Jun 7, 2016 at 5:49

Noob Coder

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sgarizvi · Accepted Answer · 2016-06-07 06:01:26Z

0

You have to specify the library files as linker flags.

g++ program.cpp -o program -lopencv_core -lopencv_highgui

For this specific program, only the core and highgui modules of OpenCV are required. The list will increase as functionality from other modules are added in the program.

answered Jun 7, 2016 at 6:01

sgarizvi

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Jaha · Accepted Answer · 2016-06-07 06:12:18Z

0

g++ -ggdb `pkg-config --cflags opencv` -o outResize *.cpp `pkg-config --libs opencv`

then compile
./run

edited Jun 7, 2016 at 6:12

answered Jun 7, 2016 at 6:06

Jaha

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