OpenCV imwrite function causes 'undefined symbol'

Question

I\'m working on a piece of software that consists of some core C++ code with python bindings. The C++ code uses a lot of OpenCV already but now I\'m trying to save an image some

Answer 1

I am not best on cmake, but you appear to have failed to link the imwrite() function.

I'm on a Mac so this will be different if you are elsewhere, but if you look in the OpenCV libraries directory, specifically in libopencv_imgcodecs.dylib like this:

nm -gUP  libopencv_imgcodecs.dylib | grep -i write

You will see something like:

__ZN2cv7imwriteERKNS_6StringERKNS_11_InputArrayERKNSt3__16vector...

That means that imgcodecs provides the function you need.

I am, I hope (thanks to @Ptaq666), reliably informed that the best way of adding this library will be to use:

find_package(OpenCV 3 REQUIRED)

followed by:

target_link_libraries(<as you already have> ${OpenCV_LIBRARIES})

---

Original suggestion

That means that imgcodecs provides the function you need, so I think you need to add that into this line in your CMakeLists.txt:

find_package(OpenCV 3 COMPONENTS core highgui imgproc REQUIRED)

I guess that will be something like:

find_package(OpenCV 3 COMPONENTS core highgui imgproc imgcodecs REQUIRED)