# CMake

**CMake** is a build system generator. It reads a project description in `CMakeLists.txt` and generates native build files (Makefiles, Ninja, Visual Studio projects, etc.) for your platform. This solves portability—describe targets and dependencies abstractly, and CMake generates platform-specific build recipes.

CMake is the de facto standard in HPC, embedded, and scientific computing. Most numerical libraries (Eigen, OpenCV, CUDA, MPI) ship with `CMakeLists.txt` and expect to be consumed via `find_package`. Knowing CMake is about reading and extending others' build scripts, not writing elaborate ones from scratch.

```bash
$ mkdir build && cd build       # out-of-source build
$ cmake ..                      # generate build system
$ cmake --build .               # invoke generator (make, ninja, ...)
$ cmake --build . --target test # run tests
```

CMake separates configuration (reading `CMakeLists.txt`, finding libraries) from building. The configuration step generates build files; the build step invokes the underlying tool. This two-step process lets you use the same CMakeLists.txt with different generators.

## Concepts

 1. [[cmake-basics|Basics]]
 2. [[cmake-cmakelists-txt|CMakeLists.txt]]
 3. [[cmake-projects-and-targets|Projects and targets]]
 4. [[cmake-executables-and-libraries|Executables and libraries]]
 5. [[cmake-variables|Variables]]
 6. [[cmake-conditionals-and-loops|Conditionals and loops]]
 7. [[cmake-functions-and-macros|Functions and macros]]
 8. [[cmake-finding-dependencies|Finding dependencies]]
 9. [[cmake-linking|Linking]]
 10. [[cmake-installation|Installation]]
 11. [[cmake-testing|Testing]]
 12. [[cmake-generators|Generators]]
 13. [[cmake-modern-practices|Modern practices]]
 14. [[cmake-subdirectories|Subdirectories]]