c++opencvcmakeraspberry-piopencv3.0

CMake error when building OpenCV - CMakeLists not match


I attempted to build OpenCV 3.1.0 on my Raspberry Pi 2B. Unfortunately, when I ran:

cmake -D CMAKE_BUILD_TYPE=RELEASE \ -D CMAKE_INSTALL_PREFIX=/usr/local \ -D INSTALL_C_EXAMPLES=OFF \ -D INSTALL_PYTHON_EXAMPLES=OFF /home/pi/Downloads/opencv-3.1.0

I received a following error:

CMake Error: The source "/home/pi/Downloads/opencv-3.1.0/CMakeLists.txt" does not match the source "/home/pi/Downloads/opencv-3.1.0/modules/CMakeLists.txt" used to generate cache. Re-run cmake with a different source directory.

I want to use OpenCV with C++ and Code::Bocks, which I have already installed. I can't find any solution on internet, so I'd be very gratefull if someone helps me. I am using Raspbian Jezzy.


Solution

  • First, I hope you do run CMake outside your sources, in a separate directory. Not doing that is really not recommended

    To understand the error message you have to know a little bit on how CMake works.

    Basically, when you run

    cd /path/to/opencv
    mkdir build
    cd build
    cmake ..
    

    CMake generates a cache in the build dir (It's a simple file named CMakeCache.txt). This file contains some information like:

    If you ever re-run CMake and change one of these values, (by re-running cmake with different arguments, setting an other generotor or moving files), CMake will complain with this kind of message.

    A good solution is then to delete the CMakeCache, or even the whole build dir to be safe.