FetchContentPopulate

FetchContentPopulate is a CMake module designed to download and configure external projects as part of a larger CMake build. It extends the capabilities of FetchContent, a CMake feature that allows dependencies to be fetched from various sources like Git repositories, archives, or local paths. FetchContentPopulate automates the process of downloading the source code, making it available within the build environment, and often performing initial configuration steps required before the dependency can be built.

The primary purpose of FetchContentPopulate is to simplify dependency management for CMake projects. Instead of manually downloading and integrating external libraries or tools, developers can declare them as dependencies within their CMakeLists.txt file. FetchContentPopulate then handles the download and preparation, ensuring that the dependency is ready to be used by the main project. This integration often involves downloading source code, extracting archives, and potentially running the dependency's own CMake configuration step.

This module is particularly useful for projects that rely on external libraries that are not available through system package managers or when reproducible builds are critical. By defining dependencies directly in the CMakeLists.txt, FetchContentPopulate ensures that the exact version of the dependency is fetched every time the project is built, regardless of the system's state. It aims to make the build process more self-contained and less prone to issues arising from external dependencies.