I have clonned the pyside2 repo using

$ git clone --recursive https://codereview.qt-project.org/pyside/pyside-setup

and installed llvm3.9 using https://askubuntu.com/a/799998/653786 But when I run

$ sudo python3 setup.py install --ignore-git --qmake=/home/tarptaeya/Qt5.10.1/5.10.1/gcc_64/bin/qmake --cmake=/usr/bin/cmake

It give the following error

-- Found PythonLibs: /usr/lib/x86_64-linux-gnu/libpython3.5m.so (found suitable version "3.5.2", minimum required is "3.3") 
PYTHON_ARCH:             64
LLMV_CONFIG:             /usr/bin/llvm-config-3.9
CMake Error at CMakeLists.txt:94 (message):
  Unable to find Clang library clang in /usr/lib/llvm-3.9.

-- Configuring incomplete, errors occurred!

Please help me to solve this problem. Thanks!

1 Answer 1


The missing package you're looking for is version 3.9 of libclang-dev (PySide2's build process uses libclang to parse the Qt C++ source), however version 3.9 is a couple years old so it may be a headache to get. If that particular version isn't important to you, apt install clang libclang-dev should be sufficient.

You will probably also need to check out the branch in the pyside-setup repository to match the Qt version that you are building with. For examplese git checkout 5.10 if you are intending to build Python bindings for Qt 5.10.

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