: Use UPDATE_DISCONNECTED to ensure that once a project is downloaded, CMake doesn't fail if you lose internet access. 🔍 Troubleshooting Common Issues
Set up a structure for very complex dependency chains.
The DownloadProject module is a popular CMake utility designed to manage external dependencies by downloading them at rather than build time. This ensures that headers and libraries are available immediately for add_subdirectory() or find_package() calls. 🚀 Why Use DownloadProject? download_project cmake
: Precisely lock dependencies to specific Git tags or URLs. Clarity : Keeps your main CMakeLists.txt clean and readable. 🛠️ How to Implement DownloadProject
: The name used to prefix the resulting variables (e.g., ${PROJ}_SOURCE_DIR ). GIT_REPOSITORY / URL : The source of the external project. GIT_TAG : The specific version, branch, or commit hash. : Use UPDATE_DISCONNECTED to ensure that once a
Standard CMake modules like ExternalProject_Add download files during the . This creates a "chicken and egg" problem: you cannot use add_subdirectory() on a project that hasn't been downloaded yet. DownloadProject solves this by:
: Downloads happen when you run CMake (Configure step). This ensures that headers and libraries are available
If you're looking to modernize your build system further, I can help you: Convert your DownloadProject setup to .