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Editorial Team
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Asked: 2026-06-03T06:52:29+00:00

I’ve successfully built a demo app using opencv on windows with the MSYS shell

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I’ve successfully built a demo app using opencv on windows with the MSYS shell environment.

I did NOT use the prebuilt opencv installer, I downloaded and compiled the source locally (this is the recommended method).

After building opencv and running make install, all the files are happily in:

/e/deps/libopencv/build/install/

I can successfully build a sample application against this using cmake directives along the lines of:

find_package(OPENCV REQUIRED)
link_directory(${OpenCV_LIB_DIR})
include_directories(${OpenCV_INCLUDE_DIRS})
target_link_libraries(target ${OpenCV_LIBS})

To be completely clear here: building the binary is successful.

Now, when I run it from the shell I get the message:

The program can't start because libopencv_core231.dll is missing from your computer. 
Try reinstalling the program to fix this problem.

So… I know where the libraries are:

$ ls /e/deps/libopencv/build/install/lib/
libopencv_calib3d231.dll.a  libopencv_features2d231.dll.a  libopencv_highgui231.dll.a     libopencv_ml231.dll.a         libopencv_video231.dll.a
libopencv_contrib231.dll.a  libopencv_flann231.dll.a       libopencv_imgproc231.dll.a  libopencv_objdetect231.dll.a
libopencv_core231.dll.a     libopencv_gpu231.dll.a         libopencv_legacy231.dll.a   libopencv_ts231.a

What now?

I guess I could try to make cmake build a static binary, but that seems pretty extreme.

How can I somehow make either 1) windows, or 2) the MSYS environment happy. Something like LD_LIBRARY_PATH on windows?

Or is this not the problem, and I’ve actually (despite appearances) somehow messed up the way the binary was compiled?

Edit:

NB. For whatever reason it seems that my libraries are .dll.a files, not .dlls (see the ls result) if that’s remotely relevant.

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1 Answer

  1. Editorial Team

    windows searches the same directory as the exe, any directory in the %PATH% (Windows) or $PATH (msys) directories, as well as a few special ones in the windows folder
    You could add /e/deps/libopencv/build/install/lib to your $PATH. I am not sure if this will work for msys, you may need to add E:\deps\libopencv\build\install\lib to %PATH% in windows instead.

    The typical solution for this if you are giving the program to others is to include a copy of the DLL in the same directory as the EXE. you can get this same effect by making a symbolic link to it with the command

    ln -s /e/deps/libopencv/build/install/lib/libopencv_core231.dll libopencv_core231.dll

    while in the /e/deps/libopencv/build/install/ directory

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