Question 1

How do I add a private GitHub repository as a dependency with CPM.cmake?

Accepted Answer

Use the standard URI format like 'gh:user/repo' and configure git to rewrite URLs with access tokens using git config, as explained in the 'Private repositories and CI' section. This avoids exposing tokens in CMake files.

Question 2

CPM.cmake vs FetchContent: what's the difference and which should I use?

Accepted Answer

CPM.cmake wraps FetchContent to add version control, caching, and a simpler API, making it better for dependency management. Use pure FetchContent if you need minimal overhead and don't require version locking or offline support.

Question 3

How to update all dependencies in a CPM.cmake project without editing CMakeLists.txt?

Accepted Answer

Use the package lock feature by including CPMUsePackageLock and building the cpm-update-package-lock target. This updates a lock file that lists all dependencies, as described in the 'Package lock' section.

Question 4

Can CPM.cmake work with vcpkg or conan packages?

Accepted Answer

Yes, by setting CPM_USE_LOCAL_PACKAGES, CPM.cmake will try find_package first, allowing integration with external managers. However, it's primarily designed for source-based dependencies and may not leverage all features of those tools.

Question 5

What happens if a dependency has a bad CMakeLists.txt file?

Accepted Answer

You may need to use DOWNLOAD_ONLY and manually create targets, as shown in the Lua snippet in the README. This adds complexity and requires extra CMake code to handle non-conforming projects.

Question 6

Is CPM.cmake good for large C++ projects with many dependencies?

Accepted Answer

It can be, but the lack of pre-built binaries and potential version conflicts in complex graphs might slow down builds. For very large projects, dedicated package managers with binary caching might be more efficient.

Question 7

How to cache dependencies offline to avoid re-downloading?

Accepted Answer

Set the CPM_SOURCE_CACHE environment variable or CMake option to a directory path. This stores downloaded sources locally, allowing offline configuration and faster subsequent builds, as detailed in the options section.

cpm

What is cpm?

Overview

Use Cases

Best For

Related Projects

Found a gem we're missing?

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions