FAQs

This section covers common needs.

Starting a new project

The easiest way to get started is to use the Scientific Python cookie, which makes a new project following the [Scientific Python Development Guidelines][]. Scikit-build-core is one of the backends you can select. The project will have a lot of tooling prepared for you as well, including pre-commit checks and a noxfile; be sure to read the guidelines to see what is there and how it works.

Another option is the pybind11 example.

In the future, a CLI interface with a new project generator is planned.

Multithreaded builds

For most generators, you can control the parallelization via a CMake define:

pip install -Ccmake.define.CMAKE_BUILD_PARALLEL_LEVEL=8 .

or an environment variable:

CMAKE_BUILD_PARALLEL_LEVEL=8 pip install .

The default generator on Unix-like platforms is Ninja, which automatically tries to run in parallel with the number of cores on your machine.

Dynamic setup.py options

While we will eventually have some dynamic options, most common needs can be moved into your CMakeLists.txt. For example, if you had a custom setup.py option (which setuptools has deprecated as well), you can make it a CMake option and then pass it with -Ccmake.define.<OPTION_NAME>=<value>. If you need to customize configuration options, try [[tool.scikit-build.overrides]]. If that is missing some value you need, please open an issue and let us know.

Finding Python

One common mistake when using FindPython is to forget to only request the Development.Module component. If you request Development, you will also require the Development.Embed component, which will require the Python libraries to be found for linking. When building a module on Unix, you do not link to Python - the Python symbols are already loaded in the interpreter. What’s more, the manylinux image (which is used to make redistributable Linux wheels) does not have the Python libraries, both to avoid this mistake, and to reduce size.