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Trouble installing opencv 4.0.0 under linux

asked 2019-01-30 12:32:26 -0500

aeroleo gravatar image

updated 2019-01-30 13:19:35 -0500

Hi, As far as I understand it, to install opencv 4.0.0 on a mint 18 linux, i need to build it from sources. So I tried (and failed).

The Website ( informs:

cd ~/<my_working_directory>
git clone
git clone

cd ~/opencv
mkdir build
cd build

so far nothing exciting. Next:

cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..

which yields:

CMake Error at CMakeLists.txt:11 (message):

  FATAL: In-source builds are not allowed.

         You should create a separate directory for build files.

-- Configuring incomplete, errors occurred!

I tried to add -DCMAKE_SOURCE_DIR and/or -DMAKE_BINARY_DIR but more or less in vain.

Can someone help me?



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did you really cd into your build folder ? shouldn't it be: mkdir build && cd build ?

berak gravatar imageberak ( 2019-01-30 12:34:54 -0500 )edit

yes, you're right. Sorry the forum is ignoring single line feeds, so i had to make double line feeds (which looks kind of strange). Yes i did cd into the right dir (otherwise it would complain about missing CMakeLists.txt.

aeroleo gravatar imageaeroleo ( 2019-01-30 12:38:45 -0500 )edit

you can also mark your code and press ctrl-k to format it properly

berak gravatar imageberak ( 2019-01-30 12:42:04 -0500 )edit

thanks, this is much more readable.

aeroleo gravatar imageaeroleo ( 2019-01-30 13:20:02 -0500 )edit

otherwise it would complain about missing CMakeLists.txt it doesn't if there is ~/<my_working_directory>/CMakeLists.txt file.

dkurt gravatar imagedkurt ( 2019-01-31 05:24:34 -0500 )edit

dkurt, you're right. On the other hand, it would have to be not just any CMakeLists.txt, but one which starts (up to line 11)just like the one for opencv. But I have no experience using cmake, maybe this is standard for all of these files.

aeroleo gravatar imageaeroleo ( 2019-01-31 05:29:15 -0500 )edit

Maybe you have some unusual characters in ~/<my_working_directory>? I.e. whitespaces, non English characters, opencv or opencv2folders names (there were some issue about it Try to clean up build folder cd build && rm -rf * and check that there is no extra files in source tree generated by cmake: cd /path/to/opencv && git status.

dkurt gravatar imagedkurt ( 2019-01-31 05:42:42 -0500 )edit

Well, there were no unusual characters, but it was on an encrypted fs (/media/veracrypt2/opencv). When I did the same on /home/etc... everything worked fine. Never would have guessed that, i thought there were good chances of wasting my time, when i did it on my home dir.

Thank you dkurt :)

aeroleo gravatar imageaeroleo ( 2019-01-31 07:47:57 -0500 )edit

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answered 2019-01-31 08:01:16 -0500

mshabunin gravatar image

As the comment says: In-source builds are forbidden

You should create build directory on the same level as source directory:

git clone
mkdir build
cd build
cmake <your-arguments> ../opencv
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Nope, I tried that one. It didn't work either. But dkurts Solution worked, so i am fine.

aeroleo gravatar imageaeroleo ( 2019-01-31 08:37:38 -0500 )edit
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Asked: 2019-01-30 12:32:26 -0500

Seen: 242 times

Last updated: Jan 31 '19