[SOLVED] OpenMP not found

Building Blender
1

Hi,

I’m building with precompiled libraries and getting this message lately:

Configuring Blender in “/home/mick/blender-git/build_linux” …
– Using pre-compiled LIBDIR: /home/mick/blender-git/blender/…/lib/linux_centos7_x86_64
– Could NOT find OpenMP_C (missing: OpenMP_gomp_LIBRARY OpenMP_pthread_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP_CXX (missing: OpenMP_gomp_LIBRARY OpenMP_pthread_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP (missing: OpenMP_C_FOUND OpenMP_CXX_FOUND)
– SSE2 SIMD instructions enabled
– Could NOT find OpenMP_C (missing: OpenMP_gomp_LIBRARY OpenMP_pthread_LIBRARY OpenMP_gomp_LIBRARY OpenMP_pthread_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP_CXX (missing: OpenMP_gomp_LIBRARY OpenMP_pthread_LIBRARY OpenMP_gomp_LIBRARY OpenMP_pthread_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP (missing: OpenMP_C_FOUND OpenMP_CXX_FOUND)
– OpenMP not found, disabling WITH_OPENMP
– Tests: Using Python executable: /home/mick/blender-git/lib/linux_centos7_x86_64/python/bin/python3.9
– Disabling render tests because tests folder does not exist at /home/mick/blender-git/blender/…/lib/tests
– Configuring done
– Generating done
– Build files have been written to: /home/mick/blender-git/build_linux

Building is successful, but I want it to build with OpenMP, so how do I fix this?
My OS has openmp 11.1.0 and openmpi 4.0.5 installed.

2

Hi, I have the same issue since I build with precompiled libs on Opensuse Tumbleweed.
My workaround is to open cmake-gui, add path to the libs and rebuild.
I have this only if it is needed to build from scratch or remove the build folder for example.
Please add your system specs, Linux distribution.

Cheers, mib

3

Could you please tell me where I have to execute
cmake-gui …/blender
If I run it in build_linux, everything is empty and I only get

Error: could not find CMAKE_PROJECT_NAME in Cache

4

Open cmake-gui, the are two fields, one is for the blender source and the other for the build directory.
You have to enable “Advanced” mode to see the missing libs.

Screenshot_20210402_213605
Screenshot_20210402_2136051600×900 153 KB

Cheers, mib

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5

I must not select an empty build directory, got it! Thanks!

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6

Unfortunately, even after changing OpenMP_pthread_LIBRARY in cmake-gui to /usr/lib64/libpthread.so (which exists) and click Configure, there still is the missing OpenMP message in cmake-gui output:

Using pre-compiled LIBDIR: /home/mick/blender-git/blender/…/lib/linux_centos7_x86_64
Could NOT find OpenMP_C (missing: OpenMP_gomp_LIBRARY) (found version “4.5”)
Could NOT find OpenMP_CXX (missing: OpenMP_gomp_LIBRARY) (found version “4.5”)
Could NOT find OpenMP (missing: OpenMP_C_FOUND OpenMP_CXX_FOUND)
SSE2 SIMD instructions enabled
Could NOT find OpenMP_C (missing: OpenMP_gomp_LIBRARY OpenMP_gomp_LIBRARY) (found version “4.5”)
Could NOT find OpenMP_CXX (missing: OpenMP_gomp_LIBRARY OpenMP_gomp_LIBRARY) (found version “4.5”)
Could NOT find OpenMP (missing: OpenMP_C_FOUND OpenMP_CXX_FOUND)
OpenMP not found, disabling WITH_OPENMP
Tests: Using Python executable: /home/mick/blender-git/lib/linux_centos7_x86_64/python/bin/python3.9
Disabling render tests because tests folder does not exist at /home/mick/blender-git/blender/…/lib/tests
Configuring done

and after clicking Generate and executing make in /home/mick/blender-git/blender/ there still is the error, too:

Configuring Blender in “/home/mick/blender-git/build_linux” …
– Using pre-compiled LIBDIR: /home/mick/blender-git/blender/…/lib/linux_centos7_x86_64
– Could NOT find OpenMP_C (missing: OpenMP_gomp_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP_CXX (missing: OpenMP_gomp_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP (missing: OpenMP_C_FOUND OpenMP_CXX_FOUND)
– SSE2 SIMD instructions enabled
– Could NOT find OpenMP_C (missing: OpenMP_gomp_LIBRARY OpenMP_gomp_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP_CXX (missing: OpenMP_gomp_LIBRARY OpenMP_gomp_LIBRARY) (found version “4.5”)
– Could NOT find OpenMP (missing: OpenMP_C_FOUND OpenMP_CXX_FOUND)
– OpenMP not found, disabling WITH_OPENMP
– Tests: Using Python executable: /home/mick/blender-git/lib/linux_centos7_x86_64/python/bin/python3.9
– Disabling render tests because tests folder does not exist at /home/mick/blender-git/blender/…/lib/tests
– Configuring done
– Generating done
– Build files have been written to: /home/mick/blender-git/build_linux

7

Which CMake version are you using?

8

I’m using CMake 3.19.7
Just noticed that CMake also reports OpenMP_gomp_LIBRARY-NOTFOUND, perhaps it will work if I fix that too, but I don’t have a libgomp.a in my system - only libgomp.so - can I use that?

With the .so, at least it seems to work:

Using pre-compiled LIBDIR: /home/mick/blender-git/blender/…/lib/linux_centos7_x86_64
Found OpenMP_C: -fopenmp (found version “4.5”)
Found OpenMP_CXX: -fopenmp (found version “4.5”)
Found OpenMP: TRUE (found version “4.5”)
SSE2 SIMD instructions enabled
Found OpenMP_C: -fopenmp (found version “4.5”)
Found OpenMP_CXX: -fopenmp (found version “4.5”)
Tests: Using Python executable: /home/mick/blender-git/lib/linux_centos7_x86_64/python/bin/python3.9
Disabling render tests because tests folder does not exist at /home/mick/blender-git/blender/…/lib/tests
Configuring done

9

I have 3.19.7 too.
… and does it build?
Sorry, forgot about libgomp, thought is is installed with pthreads.

Cheers, mib

10

Yes it does build, so the issue is fixed, thank you!

1 Like