Question

(I am new at pretty much everything that I will discuss here… apologies if the question is very basic) – I used Xcode to write some C++ code using OpenCV (dynamic libraries). The algorithm runs smoothly and I created an executable file that also works. However, it only works in my computer.

I understand that I need to use static libraries instead of dynamic libraries. I have done some research and found how to do this here: http://www.shiffman.net/2011/01/23/how-to-build-opencv-static-libraries-mac-os-x/ and here: http://www.randomsequence.com/articles/opencv-snow-leopard/.

I have followed the steps and, although I had to make a couple of changes, I was able to build “.a” files such as “libopencv_highgui.a”.

My code, however, doesn’t work anymore when I replace the libraries. I get 200+ errors. This is one of them:

Undefined symbols for architecture x86_64:
“_gzputs”, referenced from:
__ZL7icvPutsP13CvFileStoragePKc in libopencv_core.a(persistence.o)

I have searched for this question here but this is the closest I could find: Linking OpenCV libraries in Xcode (not exactly the same question).

Thanks everyone!

Answer 1

You need .a files from $OPENCV_BUILD_PATH/3rdparty/lib/.

The _gzputs from your question belongs to libzlib.a

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To link with OpenCV static libraries you also need to add all OpenCV’s dependencies to you application. The most of these dependencies comes from the opencv_highui module and the list of dependencies is dependent from your build configuration so I can’t tell you the full list. But you can find it yourself: open the CMakeCache.txt from your OpenCV build directory with any text editor and search for opencv_highgui_LIB_DEPENDS line. You need all items from that line except the word general.